Linux Kernel up to 6.16.9 fbcon fbcon_do_set_font controlled integer overflow

CVSS Meta Temp Score
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CTI Interest Score
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7.7$0-$5k0.00

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.16.9 and classified as critical. This issue affects the function fbcon_do_set_font of the component fbcon. Such manipulation of the argument controlled leads to integer overflow. This vulnerability is referenced as CVE-2025-39967. No exploit is available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.16.9 and classified as critical. Affected by this issue is the function fbcon_do_set_font of the component fbcon. The manipulation of the argument controlled with an unknown input leads to a integer overflow vulnerability. Using CWE to declare the problem leads to CWE-190. The product performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control. Impacted is confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: fbcon: fix integer overflow in fbcon_do_set_font Fix integer overflow vulnerabilities in fbcon_do_set_font() where font size calculations could overflow when handling user-controlled font parameters. The vulnerabilities occur when: 1. CALC_FONTSZ(h, pitch, charcount) performs h * pith * charcount multiplication with user-controlled values that can overflow. 2. FONT_EXTRA_WORDS * sizeof(int) + size addition can also overflow 3. This results in smaller allocations than expected, leading to buffer overflows during font data copying. Add explicit overflow checking using check_mul_overflow() and check_add_overflow() kernel helpers to safety validate all size calculations before allocation.

The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2025-39967 since 04/16/2025. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 02/27/2026).

The vulnerability scanner Nessus provides a plugin with the ID 271548 (Linux Distros Unpatched Vulnerability : CVE-2025-39967), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 5.4.300, 5.10.245, 5.15.194, 6.1.155, 6.6.109, 6.12.50 or 6.16.10 eliminates this vulnerability. Applying the patch 994bdc2d23c79087fbf7dcd9544454e8ebcef877/9c8ec14075c5317edd6b242f1be8167aa1e4e333/b8a6e85328aeb9881531dbe89bcd2637a06c3c95/a6eb9f423b3db000aaedf83367b8539f6b72dcfc/adac90bb1aaf45ca66f9db8ac100be16750ace78/4a4bac869560f943edbe3c2b032062f6673b13d3/c0c01f9aa08c8e10e10e8c9ebb5be01a4eff6eb7/1a194e6c8e1ee745e914b0b7f50fa86c89ed13fe is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (271548) and CERT Bund (WID-SEC-2025-2298). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Affected

  • Google Container-Optimized OS
  • Debian Linux
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • RESF Rocky Linux
  • Open Source Linux Kernel
  • IBM QRadar SIEM
  • Dell NetWorker

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.9
VulDB Meta Temp Score: 7.7

VulDB Base Score: 8.0
VulDB Temp Score: 7.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 7.8
NVD Vector: 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Integer overflow
CWE: CWE-190 / CWE-189
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 271548
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2025-39967

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.4.300/5.10.245/5.15.194/6.1.155/6.6.109/6.12.50/6.16.10
Patch: 994bdc2d23c79087fbf7dcd9544454e8ebcef877/9c8ec14075c5317edd6b242f1be8167aa1e4e333/b8a6e85328aeb9881531dbe89bcd2637a06c3c95/a6eb9f423b3db000aaedf83367b8539f6b72dcfc/adac90bb1aaf45ca66f9db8ac100be16750ace78/4a4bac869560f943edbe3c2b032062f6673b13d3/c0c01f9aa08c8e10e10e8c9ebb5be01a4eff6eb7/1a194e6c8e1ee745e914b0b7f50fa86c89ed13fe

Timelineinfo

04/16/2025 CVE reserved
10/15/2025 +182 days Advisory disclosed
10/15/2025 +0 days VulDB entry created
02/27/2026 +135 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2025-39967 (🔒)
GCVE (CVE): GCVE-0-2025-39967
GCVE (VulDB): GCVE-100-328640
CERT Bund: WID-SEC-2025-2298 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 10/15/2025 12:07
Updated: 02/27/2026 02:04
Changes: 10/15/2025 12:07 (60), 10/27/2025 15:01 (2), 11/03/2025 13:30 (7), 11/22/2025 13:12 (1), 12/21/2025 06:25 (1), 02/02/2026 11:04 (1), 02/03/2026 15:42 (11), 02/27/2026 02:04 (5)
Complete: 🔍
Cache ID: 216::103

VulDB is the best source for vulnerability data and more expert information about this specific topic.

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