BlackTreeCVE Intelligence
← Back to the CVE catalogue
Full vulnerability report · 2025
CVE-2022-50511High confidence

lib/fonts: fix undefined behavior in bit shift for get_default_font

Linux · Linux

5.5MediumCVSS 3.1
Recommended action
Patch only the product branches with a verified fix

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 9 structured product or package states 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 severityMediumOperational priority:Low, 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 0.16% 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: No default targetRemediation target: Normal maintenance

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 9 structured product or package states 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.

13 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 9 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 releaseSource packageVendor stateFixed versionEvidence
Debian trixietrixie · sourcelinuxVendor fix publishedDebian records a fixed source-package version for this release.6.1.4-1Debian Security Tracker ↗Source updated 6 Oct 2026
Debian bookwormbookworm · sourcelinuxVendor fix publishedDebian records a fixed source-package version for this release.6.1.4-1Debian Security Tracker ↗Source updated 6 Oct 2026
Debian forkyforky · sourcelinuxVendor fix publishedDebian records a fixed source-package version for this release.6.1.4-1Debian Security Tracker ↗Source updated 6 Oct 2026
Debian sidsid · sourcelinuxVendor fix publishedDebian records a fixed source-package version for this release.6.1.4-1Debian Security Tracker ↗Source updated 6 Oct 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-azure-6.11Affected, 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 5 Oct 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-gcp-6.11Affected, 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 5 Oct 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-hwe-6.11Affected, 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 5 Oct 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-intelAffected, 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 5 Oct 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-lowlatency-hwe-6.11Affected, 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 5 Oct 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-oem-6.11Affected, 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 5 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 5 Oct 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-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 5 Oct 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-riscvAffected, 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 5 Oct 2026
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-2025-32051

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

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 9 structured product or package states 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: lib/fonts: fix undefined behavior in bit shift for get_default_font Shifting signed 32-bit value by 31 bits is undefined, so changing significant bit to unsigned. The UBSAN warning calltrace like below: UBSAN: shift-out-of-bounds in lib/fonts/fonts.c:139:20 left shift of 1 by 31 places cannot be represented in type 'int' <TASK> dump_stack_lvl+0x7d/0xa5 dump_stack+0x15/0x1b ubsan_epilogue+0xe/0x4e __ubsan_handle_shift_out_of_bounds+0x1e7/0x20c get_default_font+0x1c7/0x1f0 fbcon_startup+0x347/0x3a0 do_take_over_console+0xce/0x270 do_fbcon_takeover+0xa1/0x170 do_fb_registered+0x2a8/0x340 fbcon_fb_registered+0x47/0xe0 register_framebuffer+0x294/0x4a0 __drm_fb_helper_initial_config_and_unlock+0x43c/0x880 [drm_kms_helper] drm_fb_helper_initial_config+0x52/0x80 [drm_kms_helper] drm_fbdev_client_hotplug+0x156/0x1b0 [drm_kms_helper] drm_fbdev_generic_setup+0xfc/0x290 [drm_kms_helper] bochs_pci_probe+0x6ca/0x772 [bochs] local_pci_probe+0x4d/0xb0 pci_device_probe+0x119/0x320 really_probe+0x181/0x550 __driver_probe_device+0xc6/0x220 driver_probe_device+0x32/0x100 __driver_attach+0x195/0x200 bus_for_each_dev+0xbb/0x120 driver_attach+0x27/0x30 bus_add_driver+0x22e/0x2f0 driver_register+0xa9/0x190 __pci_register_driver+0x90/0xa0 bochs_pci_driver_init+0x52/0x1000 [bochs] do_one_initcall+0x76/0x430 do_init_module+0x61/0x28a load_module+0x1f82/0x2e50 __do_sys_finit_module+0xf8/0x190 __x64_sys_finit_module+0x23/0x30 do_syscall_64+0x58/0x80 entry_SYSCALL_64_after_hwframe+0x63/0xcd </TASK>

What

In the Linux kernel, the following vulnerability has been resolved: lib/fonts: fix undefined behavior in bit shift for get_default_font Shifting signed 32-bit value by 31 bits is undefined, so changing significant bit to unsigned. The UBSAN warning calltrace like below: UBSAN: shift-out-of-bounds in lib/fonts/fonts.c:139:20 left shift of 1 by 31 places cannot be represented in type 'int' <TASK> dump_stack_lvl+0x7d/0xa5 dump_stack+0x15/0x1b ubsan_epilogue+0xe/0x4e __ubsan_handle_shift_out_of_bounds+0x1e7/0x20c get_default_font+0x1c7/0x1f0 fbcon_startup+0x347/0x3a0 do_take_over_console+0xce/0x270 do_fbcon_takeover+0xa1/0x170 do_fb_registered+0x2a8/0x340 fbcon_fb_registered+0x47/0xe0 register_framebuffer+0x294/0x4a0 __drm_fb_helper_initial_config_and_unlock+0x43c/0x880 [drm_kms_helper] drm_fb_helper_initial_config+0x52/0x80 [drm_kms_helper] drm_fbdev_client_hotplug+0x156/0x1b0 [drm_kms_helper] drm_fbdev_generic_setup+0xfc/0x290 [drm_kms_helper] bochs_pci_probe+0x6ca/0x772 [bochs] local_pci_probe+0x4d/0xb0 pci_device_probe+0x119/0x320 really_probe+0x181/0x550 __driver_probe_device+0xc6/0x220 driver_probe_device+0x32/0x100 __driver_attach+0x195/0x200 bus_for_each_dev+0xbb/0x120 driver_attach+0x27/0x30 bus_add_driver+0x22e/0x2f0 driver_register+0xa9/0x190 __pci_register_driver+0x90/0xa0 bochs_pci_driver_init+0x52/0x1000 [bochs] do_one_initcall+0x76/0x430 do_init_module+0x61/0x28a load_module+0x1f82/0x2e50 __do_sys_finit_module+0xf8/0x190 __x64_sys_finit_module+0x23/0x30 do_syscall_64+0x58/0x80 entry_SYSCALL_64_after_hwframe+0x63/0xcd </TASK>

Why

The current structured CVE record identifies a security weakness, but the root cause requires confirmation in the linked vendor material.

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: lib/fonts: fix undefined behavior in bit shift for get_default_font Shifting signed 32-bit value by 31 bits is undefined, so changing significant bit to unsigned. The UBSAN warning calltrace like below: UBSAN: shift-out-of-bounds in lib/fonts/fonts.c:139:20 left shift of 1 by 31 places cannot be represented in type 'int' <TASK> dump_stack_lvl+0x7d/0xa5 dump_stack+0x15/0x1b ubsan_epilogue+0xe/0x4e __ubsan_handle_shift_out_of_bounds+0x1e7/0x20c get_default_font+0x1c7/0x1f0 fbcon_startup+0x347/0x3a0 do_take_over_console+0xce/0x270 do_fbcon_takeover+0xa1/0x170 do_fb_registered+0x2a8/0x340 fbcon_fb_registered+0x47/0xe0 register_framebuffer+0x294/0x4a0 __drm_fb_helper_initial_config_and_unlock+0x43c/0x880 [drm_kms_helper] drm_fb_helper_initial_config+0x52/0x80 [drm_kms_helper] drm_fbdev_client_hotplug+0x156/0x1b0 [drm_kms_helper] drm_fbdev_generic_setup+0xfc/0x290 [drm_kms_helper] bochs_pci_probe+0x6ca/0x772 [bochs] local_pci_probe+0x4d/0xb0 pci_device_probe+0x119/0x320 really_probe+0x181/0x550 __driver_probe_device+0xc6/0x220 driver_probe_device+0x32/0x100 __driver_attach+0x195/0x200 bus_for_each_dev+0xbb/0x120 driver_attach+0x27/0x30 bus_add_driver+0x22e/0x2f0 driver_register+0xa9/0x190 __pci_register_driver+0x90/0xa0 bochs_pci_driver_init+0x52/0x1000 [bochs] do_one_initcall+0x76/0x430 do_init_module+0x61/0x28a load_module+0x1f82/0x2e50 __do_sys_finit_module+0xf8/0x190 __x64_sys_finit_module+0x23/0x30 do_syscall_64+0x58/0x80 entry_SYSCALL_64_after_hwframe+0x63/0xcd </TASK>

Why

The current structured CVE record identifies a security weakness, but the root cause requires confirmation in the linked vendor material.

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 → vulnerable operation → 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.
CWE not yet assigned
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: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.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.
A

Official authority intelligence

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

BSI · German · WID-SEC-2025-2229Linux Kernel: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen im Linux Kernel ausnutzen, um einen Denial of Service Angriff durchzuführen und andere nicht näher spezifizierte Angriffe durchzuführen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20251008Security Bulletin 08 Oct 2025

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 08 Oct 2025, published on 8 October 2025. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2025-AVI-1073Multiples vulnérabilités dans le noyau Linux de SUSE

d?id=CVE-2022-50496 Référence CVE CVE-2022-50497 https://www.cve.org/CVERecord?id=CVE-2022-50497 Référence CVE CVE-2022-50498 https://www.cve.org/CVERecord?id=CVE-2022-50498 Référence CVE CVE-2022-50499 https://www.cve.org/CVERecord?id=CVE-2022-50499 Référence CVE CVE-2022-50501 https://www.cve.org/CVERecord?id=CVE-2022-50501 Référence CVE CVE-2022-50503 https://www.cve.org/CVERecord?id=CVE-2022-50503 Référence CVE CVE-2022-50504 https://www.cve.org/CVERecord?id=CVE-2022-50504 Référence CVE CVE-2022-50505 https://www.cve.org/CVERecord?id=CVE-2022-50505 Référence CVE CVE-2022-50509 https://www.cve.org/CVERecord?id=CVE-2022-50509 Référence CVE CVE-2022-50511 https://www.cve.org/CVERecord?id=CVE-2022-50511 Référence CVE CVE-2022-50512 https://www.cve.org/CVERecord?id=CVE-2022-50512 Référence CVE CVE-2022-50513 https://www.cve.org/CVERecord?id=CVE-2022-50513 Référence CVE CVE-2022-50514 https://www.cve.org/CVERecord?id=CVE-2022-50514 Référence CVE CVE-2022-50515 https://www.cve.org/CVERecord?id=CVE-2022-50515 Référence CVE CVE-2022-50516 https://www.cve.org/CVERecord?id=CVE-2022-50516 Référence CVE CVE-2022-50519 https://www.cve.org/CVERecord?id=CVE-2022-50519 Référence CVE CVE-2022-50520 https://www.cve.org/CVERecord?id=CVE-2022-50520 Référence CVE CVE-2022-50521 https://www.cve.org/CVERecord?id=

Official advisory ↗
CERT-FR · French · CERTFR-2025-AVI-1032Multiples vulnérabilités dans le noyau Linux de SUSE

d?id=CVE-2022-50496 Référence CVE CVE-2022-50497 https://www.cve.org/CVERecord?id=CVE-2022-50497 Référence CVE CVE-2022-50498 https://www.cve.org/CVERecord?id=CVE-2022-50498 Référence CVE CVE-2022-50499 https://www.cve.org/CVERecord?id=CVE-2022-50499 Référence CVE CVE-2022-50501 https://www.cve.org/CVERecord?id=CVE-2022-50501 Référence CVE CVE-2022-50503 https://www.cve.org/CVERecord?id=CVE-2022-50503 Référence CVE CVE-2022-50504 https://www.cve.org/CVERecord?id=CVE-2022-50504 Référence CVE CVE-2022-50505 https://www.cve.org/CVERecord?id=CVE-2022-50505 Référence CVE CVE-2022-50509 https://www.cve.org/CVERecord?id=CVE-2022-50509 Référence CVE CVE-2022-50511 https://www.cve.org/CVERecord?id=CVE-2022-50511 Référence CVE CVE-2022-50512 https://www.cve.org/CVERecord?id=CVE-2022-50512 Référence CVE CVE-2022-50513 https://www.cve.org/CVERecord?id=CVE-2022-50513 Référence CVE CVE-2022-50514 https://www.cve.org/CVERecord?id=CVE-2022-50514 Référence CVE CVE-2022-50515 https://www.cve.org/CVERecord?id=CVE-2022-50515 Référence CVE CVE-2022-50516 https://www.cve.org/CVERecord?id=CVE-2022-50516 Référence CVE CVE-2022-50519 https://www.cve.org/CVERecord?id=CVE-2022-50519 Référence CVE CVE-2022-50520 https://www.cve.org/CVERecord?id=CVE-2022-50520 Référence CVE CVE-2022-50521 https://www.cve.org/CVERecord?id=

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2025-025877LinuxのLinux Kernelにおける不特定の脆弱性

Linuxカーネルのlib/fontsにおいて、32ビット符号付き整数に対する31ビットのビットシフト操作が未定義動作を引き起こす問題が修正されました。具体的には、get_default_font関数内のビットシフトを符号なし型に変更することで、UBSANによる範囲外シフトの警告を防止しています。この修正により、安全にフォントのデフォルト値を取得できるようになりました。

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
Linux: c81f717cb9e0bd91dc4b98753cb2705ab0fe2801 < e039929e36818507e90901edae87f6fa8bc81093, c81f717cb9e0bd91dc4b98753cb2705ab0fe2801 < c9a9aa02f0fa3318e0ae5774f404419a1b4759ca, c81f717cb9e0bd91dc4b98753cb2705ab0fe2801 < e83b47580a0738361772d6f24286adfdaba57e36, c81f717cb9e0bd91dc4b98753cb2705ab0fe2801 < 9c14a85e18a58c102ec223144b7edb5b345c1bea, c81f717cb9e0bd91dc4b98753cb2705ab0fe2801 < 890d91b31f4874361e0df047f57d268a7021cb12, c81f717cb9e0bd91dc4b98753cb2705ab0fe2801 < 6fe888c4d2fb174408e4540bb2d5602b9f507f90, 2.6.23
Fixed
Linux: < 2.6.23, 5.4.229 ≤ 5.4.*, 5.10.163 ≤ 5.10.*, 5.15.86 ≤ 5.15.*, 6.0.16 ≤ 6.0.*, 6.1.2 ≤ 6.1.*, 6.2 ≤ *
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 7 Oct 2025 · Last source change 11 May 2026, 19:20 UTC · CWE not yet assigned

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-2025-32051
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceUnavailable
NVD statusNVD enriched

Missing structured fields: CWE classification. Missing data is not evidence of low risk; review the primary advisory.

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-2025-32051↗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-2022-50511 · cve.blacktree.nl