Evidence used
- No CISA KEV confirmation is currently recorded.
- Exploitation requires an existing local or physical foothold with privileges.
- EPSS is 0.24% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2024
CVE-2023-52770High confidence
f2fs: split initial and dynamic conditions for extent_cache
Linux · Linux
5.5MediumCVSS 3.1
Patch only the product branches with a verified fix
Fix availability varies by productMedium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority. Verified remediation exists for at least one product or source, but 2 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityMedium→Operational priority:Low, lowered one band.downgradedsince 23 May 2026
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
- Confirm that the asset runs Linux Linux and falls inside the recorded affected range.
- Verify the installed build against the product-specific fixed version after deployment.
- Validate exposure, authentication requirements and compensating controls in the actual environment.
- Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Remediation availability differs by product scope
Verified remediation exists for at least one product or source, but 2 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
- Debian Security Tracker, Canonical Ubuntu Security: 2 affected package states with no published fix
Distribution package intelligence
5 package statesRelease-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.
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 2 affected package states 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 release | Source package | Vendor state | Fixed version | Evidence |
|---|---|---|---|---|
| Debian trixietrixie · source | linux | Vendor fix publishedDebian records a fixed source-package version for this release. | 6.5.13-1 | Debian Security Tracker ↗Source updated 6 Oct 2026 |
| Debian bookwormbookworm · source | linux | Affected, no fix publishedDebian currently tracks this release as open. | Not published in this feed | Debian Security Tracker ↗Source updated 6 Oct 2026 |
| Debian forkyforky · source | linux | Vendor fix publishedDebian records a fixed source-package version for this release. | 6.5.13-1 | Debian Security Tracker ↗Source updated 6 Oct 2026 |
| Debian sidsid · source | linux | Vendor fix publishedDebian records a fixed source-package version for this release. | 6.5.13-1 | Debian Security Tracker ↗Source updated 6 Oct 2026 |
| Ubuntu 24.04 LTSnoble · standard archive | linux-raspi-realtime | Affected, 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 feed | Canonical Ubuntu Security ↗Source updated 5 Oct 2026 |
Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority. Verified remediation exists for at least one product or source, but 2 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
Fix availability varies by product01
What, why and how
In the Linux kernel, the following vulnerability has been resolved: f2fs: split initial and dynamic conditions for extent_cache Let's allocate the extent_cache tree without dynamic conditions to avoid a missing condition causing a panic as below. # create a file w/ a compressed flag # disable the compression # panic while updating extent_cache F2FS-fs (dm-64): Swapfile: last extent is not aligned to section F2FS-fs (dm-64): Swapfile (3) is not align to section: 1) creat(), 2) ioctl(F2FS_IOC_SET_PIN_FILE), 3) fallocate(2097152 * N) Adding 124996k swap on ./swap-file. Priority:0 extents:2 across:17179494468k ================================================================== BUG: KASAN: null-ptr-deref in instrument_atomic_read_write out/common/include/linux/instrumented.h:101 [inline] BUG: KASAN: null-ptr-deref in atomic_try_cmpxchg_acquire out/common/include/asm-generic/atomic-instrumented.h:705 [inline] BUG: KASAN: null-ptr-deref in queued_write_lock out/common/include/asm-generic/qrwlock.h:92 [inline] BUG: KASAN: null-ptr-deref in __raw_write_lock out/common/include/linux/rwlock_api_smp.h:211 [inline] BUG: KASAN: null-ptr-deref in _raw_write_lock+0x5a/0x110 out/common/kernel/locking/spinlock.c:295 Write of size 4 at addr 0000000000000030 by task syz-executor154/3327 CPU: 0 PID: 3327 Comm: syz-executor154 Tainted: G O 5.10.185 #1 Hardware name: emulation qemu-x86/qemu-x86, BIOS 2023.01-21885-gb3cc1cd24d 01/01/2023 Call Trace: __dump_stack out/common/lib/dump_stack.c:77 [inline] dump_stack_lvl+0x17e/0x1c4 out/common/lib/dump_stack.c:118 __kasan_report+0x16c/0x260 out/common/mm/kasan/report.c:415 kasan_report+0x51/0x70 out/common/mm/kasan/report.c:428 kasan_check_range+0x2f3/0x340 out/common/mm/kasan/generic.c:186 __kasan_check_write+0x14/0x20 out/common/mm/kasan/shadow.c:37 instrument_atomic_read_write out/common/include/linux/instrumented.h:101 [inline] atomic_try_cmpxchg_acquire out/common/include/asm-generic/atomic-instrumented.h:705 [inline] queued_write_lock out/common/include/asm-generic/qrwlock.h:92 [inline] __raw_write_lock out/common/include/linux/rwlock_api_smp.h:211 [inline] _raw_write_lock+0x5a/0x110 out/common/kernel/locking/spinlock.c:295 __drop_extent_tree+0xdf/0x2f0 out/common/fs/f2fs/extent_cache.c:1155 f2fs_drop_extent_tree+0x17/0x30 out/common/fs/f2fs/extent_cache.c:1172 f2fs_insert_range out/common/fs/f2fs/file.c:1600 [inline] f2fs_fallocate+0x19fd/0x1f40 out/common/fs/f2fs/file.c:1764 vfs_fallocate+0x514/0x9b0 out/common/fs/open.c:310 ksys_fallocate out/common/fs/open.c:333 [inline] __do_sys_fallocate out/common/fs/open.c:341 [inline] __se_sys_fallocate out/common/fs/open.c:339 [inline] __x64_sys_fallocate+0xb8/0x100 out/common/fs/open.c:339 do_syscall_64+0x35/0x50 out/common/arch/x86/entry/common.c:46
What
In the Linux kernel, the following vulnerability has been resolved: f2fs: split initial and dynamic conditions for extent_cache Let's allocate the extent_cache tree without dynamic conditions to avoid a missing condition causing a panic as below. # create a file w/ a compressed flag # disable the compression # panic while updating extent_cache F2FS-fs (dm-64): Swapfile: last extent is not aligned to section F2FS-fs (dm-64): Swapfile (3) is not align to section: 1) creat(), 2) ioctl(F2FS_IOC_SET_PIN_FILE), 3) fallocate(2097152 * N) Adding 124996k swap on ./swap-file. Priority:0 extents:2 across:17179494468k ================================================================== BUG: KASAN: null-ptr-deref in instrument_atomic_read_write out/common/include/linux/instrumented.h:101 [inline] BUG: KASAN: null-ptr-deref in atomic_try_cmpxchg_acquire out/common/include/asm-generic/atomic-instrumented.h:705 [inline] BUG: KASAN: null-ptr-deref in queued_write_lock out/common/include/asm-generic/qrwlock.h:92 [inline] BUG: KASAN: null-ptr-deref in __raw_write_lock out/common/include/linux/rwlock_api_smp.h:211 [inline] BUG: KASAN: null-ptr-deref in _raw_write_lock+0x5a/0x110 out/common/kernel/locking/spinlock.c:295 Write of size 4 at addr 0000000000000030 by task syz-executor154/3327 CPU: 0 PID: 3327 Comm: syz-executor154 Tainted: G O 5.10.185 #1 Hardware name: emulation qemu-x86/qemu-x86, BIOS 2023.01-21885-gb3cc1cd24d 01/01/2023 Call Trace: __dump_stack out/common/lib/dump_stack.c:77 [inline] dump_stack_lvl+0x17e/0x1c4 out/common/lib/dump_stack.c:118 __kasan_report+0x16c/0x260 out/common/mm/kasan/report.c:415 kasan_report+0x51/0x70 out/common/mm/kasan/report.c:428 kasan_check_range+0x2f3/0x340 out/common/mm/kasan/generic.c:186 __kasan_check_write+0x14/0x20 out/common/mm/kasan/shadow.c:37 instrument_atomic_read_write out/common/include/linux/instrumented.h:101 [inline] atomic_try_cmpxchg_acquire out/common/include/asm-generic/atomic-instrumented.h:705 [inline] queued_write_lock out/common/include/asm-generic/qrwlock.h:92 [inline] __raw_write_lock out/common/include/linux/rwlock_api_smp.h:211 [inline] _raw_write_lock+0x5a/0x110 out/common/kernel/locking/spinlock.c:295 __drop_extent_tree+0xdf/0x2f0 out/common/fs/f2fs/extent_cache.c:1155 f2fs_drop_extent_tree+0x17/0x30 out/common/fs/f2fs/extent_cache.c:1172 f2fs_insert_range out/common/fs/f2fs/file.c:1600 [inline] f2fs_fallocate+0x19fd/0x1f40 out/common/fs/f2fs/file.c:1764 vfs_fallocate+0x514/0x9b0 out/common/fs/open.c:310 ksys_fallocate out/common/fs/open.c:333 [inline] __do_sys_fallocate out/common/fs/open.c:341 [inline] __se_sys_fallocate out/common/fs/open.c:339 [inline] __x64_sys_fallocate+0xb8/0x100 out/common/fs/open.c:339 do_syscall_64+0x35/0x50 out/common/arch/x86/entry/common.c:46
Why
The product dereferences a pointer that it expects to be valid but is NULL.
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: f2fs: split initial and dynamic conditions for extent_cache Let's allocate the extent_cache tree without dynamic conditions to avoid a missing condition causing a panic as below. # create a file w/ a compressed flag # disable the compression # panic while updating extent_cache F2FS-fs (dm-64): Swapfile: last extent is not aligned to section F2FS-fs (dm-64): Swapfile (3) is not align to section: 1) creat(), 2) ioctl(F2FS_IOC_SET_PIN_FILE), 3) fallocate(2097152 * N) Adding 124996k swap on ./swap-file. Priority:0 extents:2 across:17179494468k ================================================================== BUG: KASAN: null-ptr-deref in instrument_atomic_read_write out/common/include/linux/instrumented.h:101 [inline] BUG: KASAN: null-ptr-deref in atomic_try_cmpxchg_acquire out/common/include/asm-generic/atomic-instrumented.h:705 [inline] BUG: KASAN: null-ptr-deref in queued_write_lock out/common/include/asm-generic/qrwlock.h:92 [inline] BUG: KASAN: null-ptr-deref in __raw_write_lock out/common/include/linux/rwlock_api_smp.h:211 [inline] BUG: KASAN: null-ptr-deref in _raw_write_lock+0x5a/0x110 out/common/kernel/locking/spinlock.c:295 Write of size 4 at addr 0000000000000030 by task syz-executor154/3327 CPU: 0 PID: 3327 Comm: syz-executor154 Tainted: G O 5.10.185 #1 Hardware name: emulation qemu-x86/qemu-x86, BIOS 2023.01-21885-gb3cc1cd24d 01/01/2023 Call Trace: __dump_stack out/common/lib/dump_stack.c:77 [inline] dump_stack_lvl+0x17e/0x1c4 out/common/lib/dump_stack.c:118 __kasan_report+0x16c/0x260 out/common/mm/kasan/report.c:415 kasan_report+0x51/0x70 out/common/mm/kasan/report.c:428 kasan_check_range+0x2f3/0x340 out/common/mm/kasan/generic.c:186 __kasan_check_write+0x14/0x20 out/common/mm/kasan/shadow.c:37 instrument_atomic_read_write out/common/include/linux/instrumented.h:101 [inline] atomic_try_cmpxchg_acquire out/common/include/asm-generic/atomic-instrumented.h:705 [inline] queued_write_lock out/common/include/asm-generic/qrwlock.h:92 [inline] __raw_write_lock out/common/include/linux/rwlock_api_smp.h:211 [inline] _raw_write_lock+0x5a/0x110 out/common/kernel/locking/spinlock.c:295 __drop_extent_tree+0xdf/0x2f0 out/common/fs/f2fs/extent_cache.c:1155 f2fs_drop_extent_tree+0x17/0x30 out/common/fs/f2fs/extent_cache.c:1172 f2fs_insert_range out/common/fs/f2fs/file.c:1600 [inline] f2fs_fallocate+0x19fd/0x1f40 out/common/fs/f2fs/file.c:1764 vfs_fallocate+0x514/0x9b0 out/common/fs/open.c:310 ksys_fallocate out/common/fs/open.c:333 [inline] __do_sys_fallocate out/common/fs/open.c:341 [inline] __se_sys_fallocate out/common/fs/open.c:339 [inline] __x64_sys_fallocate+0xb8/0x100 out/common/fs/open.c:339 do_syscall_64+0x35/0x50 out/common/arch/x86/entry/common.c:46
Why
The product dereferences a pointer that it expects to be valid but is NULL.
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 No confirmed evidence
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.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 None recorded
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.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 → NULL Pointer Dereference → 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-476 ↗
CWE-476: NULL Pointer Dereference. The product dereferences a pointer that it expects to be valid but is NULL.
- 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:N/I:N/A:HCommon 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.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.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.
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
- 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 21 May 2024 · Last source change 23 May 2026, 15:27 UTC · CWE-476 · NULL Pointer Dereference
CVE recordCVE.org · 5.2
CVSS sourceNIST NVD
EPSS source FIRST · tracked since 2026-08-14
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2023-59487
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceNIST NVD
NVD statusNVD enriched
Core structured fields are present and their contributing authorities are shown above.
Material change intelligence
View recent updates ↗What changed after publication
No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.
CVE published
Fixed release or patch reference recorded
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.