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Full vulnerability report · 2024
CVE-2021-47118High confidence

pid: take a reference when initializing `cad_pid`

Linux · Linux

7.8HighCVSS 3.1
Recommended action
Patch only the product branches with a verified fix

High technical severity; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:Medium, lowered one band.downgradedsince 11 May 2026

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • Exploitation requires an existing local or physical foothold with privileges.
  • EPSS is 0.25% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict local access and enforce least privilege on affected hosts.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs Linux Linux and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: As exposure requiresRemediation target: Within 365 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Cross-source reconciliation

Remediation availability differs by product scope

Verified remediation exists for at least one product or source, but 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Distribution package intelligence

Release-specific package status

Debian, ubuntu findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.

5 package states
Package result overrides the generic status

BlackTree has verified remediation for at least one product or source, but the relevant distribution still reports no fixed package for 1 affected package state shown here. Treat those rows as affected with no fix until that distribution publishes a fixed version.

Repository candidate not checked

A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.

Distribution releaseSource packageVendor stateFixed versionEvidence
Debian trixietrixie · sourcelinuxVendor fix publishedDebian records a fixed source-package version for this release.5.10.46-1Debian Security Tracker ↗Source updated 6 Oct 2026
Debian bookwormbookworm · sourcelinuxVendor fix publishedDebian records a fixed source-package version for this release.5.10.46-1Debian Security Tracker ↗Source updated 6 Oct 2026
Debian forkyforky · sourcelinuxVendor fix publishedDebian records a fixed source-package version for this release.5.10.46-1Debian Security Tracker ↗Source updated 6 Oct 2026
Debian sidsid · sourcelinuxVendor fix publishedDebian records a fixed source-package version for this release.5.10.46-1Debian Security Tracker ↗Source updated 6 Oct 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-raspi-realtimeAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical Ubuntu Security ↗Source updated 6 Oct 2026
Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current
CVE-2021-47118 · CSAF 2.0 · revision 54 · interimSUSE Product Security TeamCVE-2021-47118
162 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • kernel-default as component of SUSE Linux Enterprise High Performance Computing 12 SP2
  • kernel-default-base as component of SUSE Linux Enterprise High Performance Computing 12 SP2
  • kernel-default-devel as component of SUSE Linux Enterprise High Performance Computing 12 SP2
  • kernel-default-man as component of SUSE Linux Enterprise High Performance Computing 12 SP2
  • kernel-devel as component of SUSE Linux Enterprise High Performance Computing 12 SP2
  • kernel-macros as component of SUSE Linux Enterprise High Performance Computing 12 SP2
  • kernel-source as component of SUSE Linux Enterprise High Performance Computing 12 SP2
  • kernel-default as component of SUSE Linux Enterprise High Performance Computing 12 SP4
  • kernel-default-base as component of SUSE Linux Enterprise High Performance Computing 12 SP4
  • kernel-default-devel as component of SUSE Linux Enterprise High Performance Computing 12 SP4
  • kernel-default-man as component of SUSE Linux Enterprise High Performance Computing 12 SP4
  • kernel-devel as component of SUSE Linux Enterprise High Performance Computing 12 SP4
Summary
In the Linux kernel, the following vulnerability has been resolved: pid: take a reference when initializing `cad_pid` During boot, kernel_init_freeable() initializes `cad_pid` to the init task's struct pid. Later on, we may change `cad_pid` via a sysctl, and when this happens proc_do_cad_pid() will increment the refcount on the new pid via get_pid(), and will decrement the refcount on the old pid via put_pid(). As we never called get_pid() when we initialized `cad_pid`, we decrement a reference we never incremented, can therefore free the init task's struct pid early. As there can be dangling references to the struct pid, we can later encounter a use-after-free (e.g. when delivering signals). This was spotted when fuzzing v5.13-rc3 with Syzkaller, but seems to have been around since the conversion of `cad_pid` to struct pid in commit 9ec52099e4b8 ("[PATCH] replace cad_pid by a struct pid") from the pre-KASAN stone age of v2.6.19. Fix this by getting a reference to the init task's struct pid when we assign it to `cad_pid`. Full KASAN splat below. ================================================================== BUG: KASAN: use-after-free in ns_of_pid include/linux/pid.h:153 [inline] BUG: KASAN: use-after-free in task_active_pid_ns+0xc0/0xc8 kernel/pid.c:509 Read of size 4 at addr ffff23794dda0004 by task syz-executor.0/273 CPU: 1 PID: 273 Comm: syz-executor.0 Not tainted 5.12.0-00001-g9aef892b2d15 #1 Hardware name: linux,dummy-virt (DT) Call trace: ns_of_pid include/linux/pid.h:153 [inline] task_active_pid_ns+0xc0/0xc8 kernel/pid.c:509 do_notify_parent+0x308/0xe60 kernel/signal.c:1950 exit_notify kernel/exit.c:682 [inline] do_exit+0x2334/0x2bd0 kernel/exit.c:845 do_group_exit+0x108/0x2c8 kernel/exit.c:922 get_signal+0x4e4/0x2a88 kernel/signal.c:2781 do_signal arch/arm64/kernel/signal.c:882 [inline] do_notify_resume+0x300/0x970 arch/arm64/kernel/signal.c:936 work_pending+0xc/0x2dc Allocated by task 0: slab_post_alloc_hook+0x50/0x5c0 mm/slab.h:516 slab_alloc_node mm/slub.c:2907 [inline] slab_alloc mm/slub.c:2915 [inline] kmem_cache_alloc+0x1f4/0x4c0 mm/slub.c:2920 alloc_pid+0xdc/0xc00 kernel/pid.c:180 copy_process+0x2794/0x5e18 kernel/fork.c:2129 kernel_clone+0x194/0x13c8 kernel/fork.c:2500 kernel_thread+0xd4/0x110 kernel/fork.c:2552 rest_init+0x44/0x4a0 init/main.c:687 arch_call_rest_init+0x1c/0x28 start_kernel+0x520/0x554 init/main.c:1064 0x0 Freed by task 270: slab_free_hook mm/slub.c:1562 [inline] slab_free_freelist_hook+0x98/0x260 mm/slub.c:1600 slab_free mm/slub.c:3161 [inline] kmem_cache_free+0x224/0x8e0 mm/slub.c:3177 put_pid.part.4+0xe0/0x1a8 kernel/pid.c:114 put_pid+0x30/0x48 kernel/pid.c:109 proc_do_cad_pid+0x190/0x1b0 kernel/sysctl.c:1401 proc_sys_call_handler+0x338/0x4b0 fs/proc/proc_sysctl.c:591 proc_sys_write+0x34/0x48 fs/proc/proc_sysctl.c:617 call_write_iter include/linux/fs.h:1977 [inline] new_sync_write+0x3ac/0x510 fs/read_write.c:518 vfs_write fs/read_write.c:605 [inline] vfs_write+0x9c4/0x1018 fs/read_write.c:585 ksys_write+0x124/0x240 fs/read_write.c:658 __do_sys_write fs/read_write.c:670 [inline] __se_sys_write fs/read_write.c:667 [inline] __arm64_sys_write+0x78/0xb0 fs/read_write.c:667 __invoke_syscall arch/arm64/kernel/syscall.c:37 [inline] invoke_syscall arch/arm64/kernel/syscall.c:49 [inline] el0_svc_common.constprop.1+0x16c/0x388 arch/arm64/kernel/syscall.c:129 do_el0_svc+0xf8/0x150 arch/arm64/kernel/syscall.c:168 el0_svc+0x28/0x38 arch/arm64/kernel/entry-common.c:416 el0_sync_handler+0x134/0x180 arch/arm64/kernel/entry-common.c:432 el0_sync+0x154/0x180 arch/arm64/kernel/entry.S:701 The buggy address belongs to the object at ffff23794dda0000 which belongs to the cache pid of size 224 The buggy address is located 4 bytes inside of 224-byte region [ff ---truncated---
Remediation
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2021-33766

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionPatch only the product branches with a verified fix

High technical severity; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
01

What, why and how

In the Linux kernel, the following vulnerability has been resolved: pid: take a reference when initializing `cad_pid` During boot, kernel_init_freeable() initializes `cad_pid` to the init task's struct pid. Later on, we may change `cad_pid` via a sysctl, and when this happens proc_do_cad_pid() will increment the refcount on the new pid via get_pid(), and will decrement the refcount on the old pid via put_pid(). As we never called get_pid() when we initialized `cad_pid`, we decrement a reference we never incremented, can therefore free the init task's struct pid early. As there can be dangling references to the struct pid, we can later encounter a use-after-free (e.g. when delivering signals). This was spotted when fuzzing v5.13-rc3 with Syzkaller, but seems to have been around since the conversion of `cad_pid` to struct pid in commit 9ec52099e4b8 ("[PATCH] replace cad_pid by a struct pid") from the pre-KASAN stone age of v2.6.19. Fix this by getting a reference to the init task's struct pid when we assign it to `cad_pid`. Full KASAN splat below. ================================================================== BUG: KASAN: use-after-free in ns_of_pid include/linux/pid.h:153 [inline] BUG: KASAN: use-after-free in task_active_pid_ns+0xc0/0xc8 kernel/pid.c:509 Read of size 4 at addr ffff23794dda0004 by task syz-executor.0/273 CPU: 1 PID: 273 Comm: syz-executor.0 Not tainted 5.12.0-00001-g9aef892b2d15 #1 Hardware name: linux,dummy-virt (DT) Call trace: ns_of_pid include/linux/pid.h:153 [inline] task_active_pid_ns+0xc0/0xc8 kernel/pid.c:509 do_notify_parent+0x308/0xe60 kernel/signal.c:1950 exit_notify kernel/exit.c:682 [inline] do_exit+0x2334/0x2bd0 kernel/exit.c:845 do_group_exit+0x108/0x2c8 kernel/exit.c:922 get_signal+0x4e4/0x2a88 kernel/signal.c:2781 do_signal arch/arm64/kernel/signal.c:882 [inline] do_notify_resume+0x300/0x970 arch/arm64/kernel/signal.c:936 work_pending+0xc/0x2dc Allocated by task 0: slab_post_alloc_hook+0x50/0x5c0 mm/slab.h:516 slab_alloc_node mm/slub.c:2907 [inline] slab_alloc mm/slub.c:2915 [inline] kmem_cache_alloc+0x1f4/0x4c0 mm/slub.c:2920 alloc_pid+0xdc/0xc00 kernel/pid.c:180 copy_process+0x2794/0x5e18 kernel/fork.c:2129 kernel_clone+0x194/0x13c8 kernel/fork.c:2500 kernel_thread+0xd4/0x110 kernel/fork.c:2552 rest_init+0x44/0x4a0 init/main.c:687 arch_call_rest_init+0x1c/0x28 start_kernel+0x520/0x554 init/main.c:1064 0x0 Freed by task 270: slab_free_hook mm/slub.c:1562 [inline] slab_free_freelist_hook+0x98/0x260 mm/slub.c:1600 slab_free mm/slub.c:3161 [inline] kmem_cache_free+0x224/0x8e0 mm/slub.c:3177 put_pid.part.4+0xe0/0x1a8 kernel/pid.c:114 put_pid+0x30/0x48 kernel/pid.c:109 proc_do_cad_pid+0x190/0x1b0 kernel/sysctl.c:1401 proc_sys_call_handler+0x338/0x4b0 fs/proc/proc_sysctl.c:591 proc_sys_write+0x34/0x48 fs/proc/proc_sysctl.c:617 call_write_iter include/linux/fs.h:1977 [inline] new_sync_write+0x3ac/0x510 fs/read_write.c:518 vfs_write fs/read_write.c:605 [inline] vfs_write+0x9c4/0x1018 fs/read_write.c:585 ksys_write+0x124/0x240 fs/read_write.c:658 __do_sys_write fs/read_write.c:670 [inline] __se_sys_write fs/read_write.c:667 [inline] __arm64_sys_write+0x78/0xb0 fs/read_write.c:667 __invoke_syscall arch/arm64/kernel/syscall.c:37 [inline] invoke_syscall arch/arm64/kernel/syscall.c:49 [inline] el0_svc_common.constprop.1+0x16c/0x388 arch/arm64/kernel/syscall.c:129 do_el0_svc+0xf8/0x150 arch/arm64/kernel/syscall.c:168 el0_svc+0x28/0x38 arch/arm64/kernel/entry-common.c:416 el0_sync_handler+0x134/0x180 arch/arm64/kernel/entry-common.c:432 el0_sync+0x154/0x180 arch/arm64/kernel/entry.S:701 The buggy address belongs to the object at ffff23794dda0000 which belongs to the cache pid of size 224 The buggy address is located 4 bytes inside of 224-byte region [ff ---truncated---

What

In the Linux kernel, the following vulnerability has been resolved: pid: take a reference when initializing `cad_pid` During boot, kernel_init_freeable() initializes `cad_pid` to the init task's struct pid. Later on, we may change `cad_pid` via a sysctl, and when this happens proc_do_cad_pid() will increment the refcount on the new pid via get_pid(), and will decrement the refcount on the old pid via put_pid(). As we never called get_pid() when we initialized `cad_pid`, we decrement a reference we never incremented, can therefore free the init task's struct pid early. As there can be dangling references to the struct pid, we can later encounter a use-after-free (e.g. when delivering signals). This was spotted when fuzzing v5.13-rc3 with Syzkaller, but seems to have been around since the conversion of `cad_pid` to struct pid in commit 9ec52099e4b8 ("[PATCH] replace cad_pid by a struct pid") from the pre-KASAN stone age of v2.6.19. Fix this by getting a reference to the init task's struct pid when we assign it to `cad_pid`. Full KASAN splat below. ================================================================== BUG: KASAN: use-after-free in ns_of_pid include/linux/pid.h:153 [inline] BUG: KASAN: use-after-free in task_active_pid_ns+0xc0/0xc8 kernel/pid.c:509 Read of size 4 at addr ffff23794dda0004 by task syz-executor.0/273 CPU: 1 PID: 273 Comm: syz-executor.0 Not tainted 5.12.0-00001-g9aef892b2d15 #1 Hardware name: linux,dummy-virt (DT) Call trace: ns_of_pid include/linux/pid.h:153 [inline] task_active_pid_ns+0xc0/0xc8 kernel/pid.c:509 do_notify_parent+0x308/0xe60 kernel/signal.c:1950 exit_notify kernel/exit.c:682 [inline] do_exit+0x2334/0x2bd0 kernel/exit.c:845 do_group_exit+0x108/0x2c8 kernel/exit.c:922 get_signal+0x4e4/0x2a88 kernel/signal.c:2781 do_signal arch/arm64/kernel/signal.c:882 [inline] do_notify_resume+0x300/0x970 arch/arm64/kernel/signal.c:936 work_pending+0xc/0x2dc Allocated by task 0: slab_post_alloc_hook+0x50/0x5c0 mm/slab.h:516 slab_alloc_node mm/slub.c:2907 [inline] slab_alloc mm/slub.c:2915 [inline] kmem_cache_alloc+0x1f4/0x4c0 mm/slub.c:2920 alloc_pid+0xdc/0xc00 kernel/pid.c:180 copy_process+0x2794/0x5e18 kernel/fork.c:2129 kernel_clone+0x194/0x13c8 kernel/fork.c:2500 kernel_thread+0xd4/0x110 kernel/fork.c:2552 rest_init+0x44/0x4a0 init/main.c:687 arch_call_rest_init+0x1c/0x28 start_kernel+0x520/0x554 init/main.c:1064 0x0 Freed by task 270: slab_free_hook mm/slub.c:1562 [inline] slab_free_freelist_hook+0x98/0x260 mm/slub.c:1600 slab_free mm/slub.c:3161 [inline] kmem_cache_free+0x224/0x8e0 mm/slub.c:3177 put_pid.part.4+0xe0/0x1a8 kernel/pid.c:114 put_pid+0x30/0x48 kernel/pid.c:109 proc_do_cad_pid+0x190/0x1b0 kernel/sysctl.c:1401 proc_sys_call_handler+0x338/0x4b0 fs/proc/proc_sysctl.c:591 proc_sys_write+0x34/0x48 fs/proc/proc_sysctl.c:617 call_write_iter include/linux/fs.h:1977 [inline] new_sync_write+0x3ac/0x510 fs/read_write.c:518 vfs_write fs/read_write.c:605 [inline] vfs_write+0x9c4/0x1018 fs/read_write.c:585 ksys_write+0x124/0x240 fs/read_write.c:658 __do_sys_write fs/read_write.c:670 [inline] __se_sys_write fs/read_write.c:667 [inline] __arm64_sys_write+0x78/0xb0 fs/read_write.c:667 __invoke_syscall arch/arm64/kernel/syscall.c:37 [inline] invoke_syscall arch/arm64/kernel/syscall.c:49 [inline] el0_svc_common.constprop.1+0x16c/0x388 arch/arm64/kernel/syscall.c:129 do_el0_svc+0xf8/0x150 arch/arm64/kernel/syscall.c:168 el0_svc+0x28/0x38 arch/arm64/kernel/entry-common.c:416 el0_sync_handler+0x134/0x180 arch/arm64/kernel/entry-common.c:432 el0_sync+0x154/0x180 arch/arm64/kernel/entry.S:701 The buggy address belongs to the object at ffff23794dda0000 which belongs to the cache pid of size 224 The buggy address is located 4 bytes inside of 224-byte region [ff ---truncated---

Why

The program can continue using memory after it has been released, producing unsafe and attacker-influenceable behaviour.

How

An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

In the Linux kernel, the following vulnerability has been resolved: pid: take a reference when initializing `cad_pid` During boot, kernel_init_freeable() initializes `cad_pid` to the init task's struct pid. Later on, we may change `cad_pid` via a sysctl, and when this happens proc_do_cad_pid() will increment the refcount on the new pid via get_pid(), and will decrement the refcount on the old pid via put_pid(). As we never called get_pid() when we initialized `cad_pid`, we decrement a reference we never incremented, can therefore free the init task's struct pid early. As there can be dangling references to the struct pid, we can later encounter a use-after-free (e.g. when delivering signals). This was spotted when fuzzing v5.13-rc3 with Syzkaller, but seems to have been around since the conversion of `cad_pid` to struct pid in commit 9ec52099e4b8 ("[PATCH] replace cad_pid by a struct pid") from the pre-KASAN stone age of v2.6.19. Fix this by getting a reference to the init task's struct pid when we assign it to `cad_pid`. Full KASAN splat below. ================================================================== BUG: KASAN: use-after-free in ns_of_pid include/linux/pid.h:153 [inline] BUG: KASAN: use-after-free in task_active_pid_ns+0xc0/0xc8 kernel/pid.c:509 Read of size 4 at addr ffff23794dda0004 by task syz-executor.0/273 CPU: 1 PID: 273 Comm: syz-executor.0 Not tainted 5.12.0-00001-g9aef892b2d15 #1 Hardware name: linux,dummy-virt (DT) Call trace: ns_of_pid include/linux/pid.h:153 [inline] task_active_pid_ns+0xc0/0xc8 kernel/pid.c:509 do_notify_parent+0x308/0xe60 kernel/signal.c:1950 exit_notify kernel/exit.c:682 [inline] do_exit+0x2334/0x2bd0 kernel/exit.c:845 do_group_exit+0x108/0x2c8 kernel/exit.c:922 get_signal+0x4e4/0x2a88 kernel/signal.c:2781 do_signal arch/arm64/kernel/signal.c:882 [inline] do_notify_resume+0x300/0x970 arch/arm64/kernel/signal.c:936 work_pending+0xc/0x2dc Allocated by task 0: slab_post_alloc_hook+0x50/0x5c0 mm/slab.h:516 slab_alloc_node mm/slub.c:2907 [inline] slab_alloc mm/slub.c:2915 [inline] kmem_cache_alloc+0x1f4/0x4c0 mm/slub.c:2920 alloc_pid+0xdc/0xc00 kernel/pid.c:180 copy_process+0x2794/0x5e18 kernel/fork.c:2129 kernel_clone+0x194/0x13c8 kernel/fork.c:2500 kernel_thread+0xd4/0x110 kernel/fork.c:2552 rest_init+0x44/0x4a0 init/main.c:687 arch_call_rest_init+0x1c/0x28 start_kernel+0x520/0x554 init/main.c:1064 0x0 Freed by task 270: slab_free_hook mm/slub.c:1562 [inline] slab_free_freelist_hook+0x98/0x260 mm/slub.c:1600 slab_free mm/slub.c:3161 [inline] kmem_cache_free+0x224/0x8e0 mm/slub.c:3177 put_pid.part.4+0xe0/0x1a8 kernel/pid.c:114 put_pid+0x30/0x48 kernel/pid.c:109 proc_do_cad_pid+0x190/0x1b0 kernel/sysctl.c:1401 proc_sys_call_handler+0x338/0x4b0 fs/proc/proc_sysctl.c:591 proc_sys_write+0x34/0x48 fs/proc/proc_sysctl.c:617 call_write_iter include/linux/fs.h:1977 [inline] new_sync_write+0x3ac/0x510 fs/read_write.c:518 vfs_write fs/read_write.c:605 [inline] vfs_write+0x9c4/0x1018 fs/read_write.c:585 ksys_write+0x124/0x240 fs/read_write.c:658 __do_sys_write fs/read_write.c:670 [inline] __se_sys_write fs/read_write.c:667 [inline] __arm64_sys_write+0x78/0xb0 fs/read_write.c:667 __invoke_syscall arch/arm64/kernel/syscall.c:37 [inline] invoke_syscall arch/arm64/kernel/syscall.c:49 [inline] el0_svc_common.constprop.1+0x16c/0x388 arch/arm64/kernel/syscall.c:129 do_el0_svc+0xf8/0x150 arch/arm64/kernel/syscall.c:168 el0_svc+0x28/0x38 arch/arm64/kernel/entry-common.c:416 el0_sync_handler+0x134/0x180 arch/arm64/kernel/entry-common.c:432 el0_sync+0x154/0x180 arch/arm64/kernel/entry.S:701 The buggy address belongs to the object at ffff23794dda0000 which belongs to the cache pid of size 224 The buggy address is located 4 bytes inside of 224-byte region [ff ---truncated---

Why

The program can continue using memory after it has been released, producing unsafe and attacker-influenceable behaviour.

How

An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
local access → Use After Free → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Local
Privileges required
Low: a basic authenticated account is required
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-416 ↗

CWE-416: Use After Free. The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRLowPrivileges required: The attacker needs basic user-level privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
The issue can support a local privilege or sandbox boundary transition; normal system utilities may then be available in the gained context.
CWE-416
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

BSI · German · WID-SEC-2024-0652Linux Kernel: Mehrere Schwachstellen ermöglichen Denial of Service

Ein lokaler Angreifer kann mehrere Schwachstellen im Linux-Kernel ausnutzen, um einen Denial-of-Service-Zustand herbeizuführen oder einen nicht spezifizierten Angriff durchzuführen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20240320Security Bulletin 20 Mar 2024

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 20 Mar 2024, published on 20 March 2024. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2025-AVI-0022Multiples vulnérabilités dans le noyau Linux d'Ubuntu

/notices/USN-7196-1 Référence CVE CVE-2020-12351 https://www.cve.org/CVERecord?id=CVE-2020-12351 Référence CVE CVE-2020-12352 https://www.cve.org/CVERecord?id=CVE-2020-12352 Référence CVE CVE-2020-24490 https://www.cve.org/CVERecord?id=CVE-2020-24490 Référence CVE CVE-2021-47001 https://www.cve.org/CVERecord?id=CVE-2021-47001 Référence CVE CVE-2021-47076 https://www.cve.org/CVERecord?id=CVE-2021-47076 Référence CVE CVE-2021-47082 https://www.cve.org/CVERecord?id=CVE-2021-47082 Référence CVE CVE-2021-47086 https://www.cve.org/CVERecord?id=CVE-2021-47086 Référence CVE CVE-2021-47101 https://www.cve.org/CVERecord?id=CVE-2021-47101 Référence CVE CVE-2021-47118 https://www.cve.org/CVERecord?id=CVE-2021-47118 Référence CVE CVE-2021-47501 https://www.cve.org/CVERecord?id=CVE-2021-47501 Référence CVE CVE-2022-36402 https://www.cve.org/CVERecord?id=CVE-2022-36402 Référence CVE CVE-2022-38096 https://www.cve.org/CVERecord?id=CVE-2022-38096 Référence CVE CVE-2022-48666 https://www.cve.org/CVERecord?id=CVE-2022-48666 Référence CVE CVE-2022-48733 https://www.cve.org/CVERecord?id=CVE-2022-48733 Référence CVE CVE-2022-48938 https://www.cve.org/CVERecord?id=CVE-2022-48938 Référence CVE CVE-2022-48943 https://www.cve.org/CVERecord?id=CVE-2022-48943 Référence CVE CVE-2023-35827 https://www.cve.org/CVERecord?id=

Official advisory ↗
CERT-FR · French · CERTFR-2024-AVI-0741Multiples vulnérabilités dans Juniper Secure Analytics

d?id=CVE-2021-40153 Référence CVE CVE-2021-41072 https://www.cve.org/CVERecord?id=CVE-2021-41072 Référence CVE CVE-2021-46909 https://www.cve.org/CVERecord?id=CVE-2021-46909 Référence CVE CVE-2021-46934 https://www.cve.org/CVERecord?id=CVE-2021-46934 Référence CVE CVE-2021-46972 https://www.cve.org/CVERecord?id=CVE-2021-46972 Référence CVE CVE-2021-47013 https://www.cve.org/CVERecord?id=CVE-2021-47013 Référence CVE CVE-2021-47055 https://www.cve.org/CVERecord?id=CVE-2021-47055 Référence CVE CVE-2021-47069 https://www.cve.org/CVERecord?id=CVE-2021-47069 Référence CVE CVE-2021-47073 https://www.cve.org/CVERecord?id=CVE-2021-47073 Référence CVE CVE-2021-47118 https://www.cve.org/CVERecord?id=CVE-2021-47118 Référence CVE CVE-2021-47153 https://www.cve.org/CVERecord?id=CVE-2021-47153 Référence CVE CVE-2021-47171 https://www.cve.org/CVERecord?id=CVE-2021-47171 Référence CVE CVE-2021-47185 https://www.cve.org/CVERecord?id=CVE-2021-47185 Référence CVE CVE-2021-47236 https://www.cve.org/CVERecord?id=CVE-2021-47236 Référence CVE CVE-2021-47310 https://www.cve.org/CVERecord?id=CVE-2021-47310 Référence CVE CVE-2021-47311 https://www.cve.org/CVERecord?id=CVE-2021-47311 Référence CVE CVE-2021-47353 https://www.cve.org/CVERecord?id=CVE-2021-47353 Référence CVE CVE-2021-47356 https://www.cve.org/CVERecord?id=

Official advisory ↗
CERT-FR · French · CERTFR-2024-AVI-0646Multiples vulnérabilités dans les produits IBM

d?id=CVE-2018-25091 Référence CVE CVE-2019-20372 https://www.cve.org/CVERecord?id=CVE-2019-20372 Référence CVE CVE-2019-25162 https://www.cve.org/CVERecord?id=CVE-2019-25162 Référence CVE CVE-2020-36777 https://www.cve.org/CVERecord?id=CVE-2020-36777 Référence CVE CVE-2021-33198 https://www.cve.org/CVERecord?id=CVE-2021-33198 Référence CVE CVE-2021-34558 https://www.cve.org/CVERecord?id=CVE-2021-34558 Référence CVE CVE-2021-46934 https://www.cve.org/CVERecord?id=CVE-2021-46934 Référence CVE CVE-2021-47013 https://www.cve.org/CVERecord?id=CVE-2021-47013 Référence CVE CVE-2021-47055 https://www.cve.org/CVERecord?id=CVE-2021-47055 Référence CVE CVE-2021-47118 https://www.cve.org/CVERecord?id=CVE-2021-47118 Référence CVE CVE-2021-47153 https://www.cve.org/CVERecord?id=CVE-2021-47153 Référence CVE CVE-2021-47171 https://www.cve.org/CVERecord?id=CVE-2021-47171 Référence CVE CVE-2021-47185 https://www.cve.org/CVERecord?id=CVE-2021-47185 Référence CVE CVE-2022-2879 https://www.cve.org/CVERecord?id=CVE-2022-2879 Référence CVE CVE-2022-2880 https://www.cve.org/CVERecord?id=CVE-2022-2880 Référence CVE CVE-2022-38096 https://www.cve.org/CVERecord?id=CVE-2022-38096 Référence CVE CVE-2022-41715 https://www.cve.org/CVERecord?id=CVE-2022-41715 Référence CVE CVE-2022-48624 https://www.cve.org/CVERecord?id=CVE-

Official advisory ↗
CERT-FR · French · CERTFR-2024-AVI-0471Multiples vulnérabilités dans le noyau Linux de Red Hat

s.redhat.com/errata/RHSA-2024:3618 Bulletin de sécurité Red Hat RHSA-2024:3619 du 05 juin 2024 https://access.redhat.com/errata/RHSA-2024:3619 Bulletin de sécurité Red Hat RHSA-2024:3627 du 05 juin 2024 https://access.redhat.com/errata/RHSA-2024:3627 Référence CVE CVE-2019-25162 https://www.cve.org/CVERecord?id=CVE-2019-25162 Référence CVE CVE-2020-36777 https://www.cve.org/CVERecord?id=CVE-2020-36777 Référence CVE CVE-2021-46934 https://www.cve.org/CVERecord?id=CVE-2021-46934 Référence CVE CVE-2021-47013 https://www.cve.org/CVERecord?id=CVE-2021-47013 Référence CVE CVE-2021-47055 https://www.cve.org/CVERecord?id=CVE-2021-47055 Référence CVE CVE-2021-47118 https://www.cve.org/CVERecord?id=CVE-2021-47118 Référence CVE CVE-2021-47153 https://www.cve.org/CVERecord?id=CVE-2021-47153 Référence CVE CVE-2021-47171 https://www.cve.org/CVERecord?id=CVE-2021-47171 Référence CVE CVE-2021-47185 https://www.cve.org/CVERecord?id=CVE-2021-47185 Référence CVE CVE-2022-48627 https://www.cve.org/CVERecord?id=CVE-2022-48627 Référence CVE CVE-2022-48669 https://www.cve.org/CVERecord?id=CVE-2022-48669 Référence CVE CVE-2023-2166 https://www.cve.org/CVERecord?id=CVE-2023-2166 Référence CVE CVE-2023-2176 https://www.cve.org/CVERecord?id=CVE-2023-2176 Référence CVE CVE-2023-52439 https://www.cve.org/CVERecord?id=CVE-

Official advisory ↗
CERT-FR · French · CERTFR-2024-AVI-0458Multiples vulnérabilités dans le noyau Linux de SUSE

d?id=CVE-2021-47071 Référence CVE CVE-2021-47073 https://www.cve.org/CVERecord?id=CVE-2021-47073 Référence CVE CVE-2021-47100 https://www.cve.org/CVERecord?id=CVE-2021-47100 Référence CVE CVE-2021-47101 https://www.cve.org/CVERecord?id=CVE-2021-47101 Référence CVE CVE-2021-47104 https://www.cve.org/CVERecord?id=CVE-2021-47104 Référence CVE CVE-2021-47110 https://www.cve.org/CVERecord?id=CVE-2021-47110 Référence CVE CVE-2021-47112 https://www.cve.org/CVERecord?id=CVE-2021-47112 Référence CVE CVE-2021-47114 https://www.cve.org/CVERecord?id=CVE-2021-47114 Référence CVE CVE-2021-47117 https://www.cve.org/CVERecord?id=CVE-2021-47117 Référence CVE CVE-2021-47118 https://www.cve.org/CVERecord?id=CVE-2021-47118 Référence CVE CVE-2021-47119 https://www.cve.org/CVERecord?id=CVE-2021-47119 Référence CVE CVE-2021-47138 https://www.cve.org/CVERecord?id=CVE-2021-47138 Référence CVE CVE-2021-47141 https://www.cve.org/CVERecord?id=CVE-2021-47141 Référence CVE CVE-2021-47142 https://www.cve.org/CVERecord?id=CVE-2021-47142 Référence CVE CVE-2021-47143 https://www.cve.org/CVERecord?id=CVE-2021-47143 Référence CVE CVE-2021-47146 https://www.cve.org/CVERecord?id=CVE-2021-47146 Référence CVE CVE-2021-47149 https://www.cve.org/CVERecord?id=CVE-2021-47149 Référence CVE CVE-2021-47150 https://www.cve.org/CVERecord?id=

Official advisory ↗
CERT-FR · French · CERTFR-2024-AVI-0440Multiples vulnérabilités dans le noyau Linux de SUSE

d?id=CVE-2021-47071 Référence CVE CVE-2021-47073 https://www.cve.org/CVERecord?id=CVE-2021-47073 Référence CVE CVE-2021-47100 https://www.cve.org/CVERecord?id=CVE-2021-47100 Référence CVE CVE-2021-47101 https://www.cve.org/CVERecord?id=CVE-2021-47101 Référence CVE CVE-2021-47104 https://www.cve.org/CVERecord?id=CVE-2021-47104 Référence CVE CVE-2021-47110 https://www.cve.org/CVERecord?id=CVE-2021-47110 Référence CVE CVE-2021-47112 https://www.cve.org/CVERecord?id=CVE-2021-47112 Référence CVE CVE-2021-47114 https://www.cve.org/CVERecord?id=CVE-2021-47114 Référence CVE CVE-2021-47117 https://www.cve.org/CVERecord?id=CVE-2021-47117 Référence CVE CVE-2021-47118 https://www.cve.org/CVERecord?id=CVE-2021-47118 Référence CVE CVE-2021-47119 https://www.cve.org/CVERecord?id=CVE-2021-47119 Référence CVE CVE-2021-47138 https://www.cve.org/CVERecord?id=CVE-2021-47138 Référence CVE CVE-2021-47141 https://www.cve.org/CVERecord?id=CVE-2021-47141 Référence CVE CVE-2021-47142 https://www.cve.org/CVERecord?id=CVE-2021-47142 Référence CVE CVE-2021-47143 https://www.cve.org/CVERecord?id=CVE-2021-47143 Référence CVE CVE-2021-47146 https://www.cve.org/CVERecord?id=CVE-2021-47146 Référence CVE CVE-2021-47149 https://www.cve.org/CVERecord?id=CVE-2021-47149 Référence CVE CVE-2021-47150 https://www.cve.org/CVERecord?id=

Official advisory ↗
CERT-FR · French · CERTFR-2024-AVI-0420Multiples vulnérabilités dans le noyau Linux de SUSE

d?id=CVE-2021-47074 Référence CVE CVE-2021-47100 https://www.cve.org/CVERecord?id=CVE-2021-47100 Référence CVE CVE-2021-47101 https://www.cve.org/CVERecord?id=CVE-2021-47101 Référence CVE CVE-2021-47104 https://www.cve.org/CVERecord?id=CVE-2021-47104 Référence CVE CVE-2021-47110 https://www.cve.org/CVERecord?id=CVE-2021-47110 Référence CVE CVE-2021-47112 https://www.cve.org/CVERecord?id=CVE-2021-47112 Référence CVE CVE-2021-47113 https://www.cve.org/CVERecord?id=CVE-2021-47113 Référence CVE CVE-2021-47114 https://www.cve.org/CVERecord?id=CVE-2021-47114 Référence CVE CVE-2021-47117 https://www.cve.org/CVERecord?id=CVE-2021-47117 Référence CVE CVE-2021-47118 https://www.cve.org/CVERecord?id=CVE-2021-47118 Référence CVE CVE-2021-47119 https://www.cve.org/CVERecord?id=CVE-2021-47119 Référence CVE CVE-2021-47131 https://www.cve.org/CVERecord?id=CVE-2021-47131 Référence CVE CVE-2021-47138 https://www.cve.org/CVERecord?id=CVE-2021-47138 Référence CVE CVE-2021-47141 https://www.cve.org/CVERecord?id=CVE-2021-47141 Référence CVE CVE-2021-47142 https://www.cve.org/CVERecord?id=CVE-2021-47142 Référence CVE CVE-2021-47143 https://www.cve.org/CVERecord?id=CVE-2021-47143 Référence CVE CVE-2021-47146 https://www.cve.org/CVERecord?id=CVE-2021-47146 Référence CVE CVE-2021-47149 https://www.cve.org/CVERecord?id=

Official advisory ↗
CERT-FR · French · CERTFR-2024-AVI-0363Multiples vulnérabilités dans le noyau Linux de SUSE

d?id=CVE-2021-47104 Référence CVE CVE-2021-47105 https://www.cve.org/CVERecord?id=CVE-2021-47105 Référence CVE CVE-2021-47107 https://www.cve.org/CVERecord?id=CVE-2021-47107 Référence CVE CVE-2021-47108 https://www.cve.org/CVERecord?id=CVE-2021-47108 Référence CVE CVE-2021-47109 https://www.cve.org/CVERecord?id=CVE-2021-47109 Référence CVE CVE-2021-47110 https://www.cve.org/CVERecord?id=CVE-2021-47110 Référence CVE CVE-2021-47112 https://www.cve.org/CVERecord?id=CVE-2021-47112 Référence CVE CVE-2021-47114 https://www.cve.org/CVERecord?id=CVE-2021-47114 Référence CVE CVE-2021-47117 https://www.cve.org/CVERecord?id=CVE-2021-47117 Référence CVE CVE-2021-47118 https://www.cve.org/CVERecord?id=CVE-2021-47118 Référence CVE CVE-2021-47119 https://www.cve.org/CVERecord?id=CVE-2021-47119 Référence CVE CVE-2021-47120 https://www.cve.org/CVERecord?id=CVE-2021-47120 Référence CVE CVE-2021-47130 https://www.cve.org/CVERecord?id=CVE-2021-47130 Référence CVE CVE-2021-47136 https://www.cve.org/CVERecord?id=CVE-2021-47136 Référence CVE CVE-2021-47137 https://www.cve.org/CVERecord?id=CVE-2021-47137 Référence CVE CVE-2021-47138 https://www.cve.org/CVERecord?id=CVE-2021-47138 Référence CVE CVE-2021-47139 https://www.cve.org/CVERecord?id=CVE-2021-47139 Référence CVE CVE-2021-47141 https://www.cve.org/CVERecord?id=

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2021-021630Linux の Linux Kernel における解放済みメモリの使用に関する脆弱性

Linux の Linux Kernel には、解放済みメモリの使用に関する脆弱性が存在します。

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Fix availability varies by product
Affected
Fixed
Linux: < 2.6.19, 4.4.272 ≤ 4.4.*, 4.9.272 ≤ 4.9.*, 4.14.236 ≤ 4.14.*, 4.19.194 ≤ 4.19.*, 5.4.125 ≤ 5.4.*, 5.10.43 ≤ 5.10.*, 5.12.10 ≤ 5.12.*, 5.13 ≤ *
Action
Use the product-specific evidence above. Patch only products with a verified fixed release, and keep every affected or under-investigation state without a matching fix in the remediation queue.
Workaround
No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04

Evidence and provenance

Published 15 Mar 2024 · Last source change 11 May 2026, 13:48 UTC · CWE-416 · Use After Free

CVE recordCVE.org · 5.2
CVSS sourceNIST NVD
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2021-33766
Product sourceVendor CSAF · SUSE Product Security Team
Remediation sourceVendor CSAF · SUSE Product Security Team
CWE sourceNIST NVD
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2021-33766↗Vendor CSAF · SUSE Product Security Team↗CVE authority or vendor reference↗Patch or update reference↗Patch or update reference↗Patch or update reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2021-47118 · cve.blacktree.nl