Linux Kernel up to 6.1.153/6.6.107/6.12.48/6.16.8 af_alg af_alg_sendmsg denial of service

CVSS Meta Temp Score
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CTI Interest Score
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5.5$0-$5k0.00

Summaryinfo

A vulnerability identified as critical has been detected in Linux Kernel up to 6.1.153/6.6.107/6.12.48/6.16.8. This affects the function af_alg_sendmsg of the component af_alg. Performing a manipulation results in denial of service. This vulnerability is identified as CVE-2025-39931. There is not any exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.1.153/6.6.107/6.12.48/6.16.8. It has been classified as critical. This affects the function af_alg_sendmsg of the component af_alg. The manipulation with an unknown input leads to a denial of service vulnerability. CWE is classifying the issue as CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. This is going to have an impact on availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: crypto: af_alg - Set merge to zero early in af_alg_sendmsg If an error causes af_alg_sendmsg to abort, ctx->merge may contain a garbage value from the previous loop. This may then trigger a crash on the next entry into af_alg_sendmsg when it attempts to do a merge that can't be done. Fix this by setting ctx->merge to zero near the start of the loop.

The advisory is shared at git.kernel.org. This vulnerability is uniquely identified as CVE-2025-39931 since 04/16/2025. Technical details are known, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 269453 (Linux Distros Unpatched Vulnerability : CVE-2025-39931), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.1.154, 6.6.108, 6.12.49 or 6.16.9 eliminates this vulnerability. Applying the patch 6241b9e2809b12da9130894cf5beddf088dc1b8a/2374c11189ef704a3e4863646369f1b8e6a27d71/24c1106504c625fabd3b7229611af617b4c27ac7/045ee26aa3920a47ec46d7fcb302420bf01fd753/9574b2330dbd2b5459b74d3b5e9619d39299fc6f 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 (269453) and CERT Bund (WID-SEC-2025-2194). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Affected

  • Google Container-Optimized OS
  • Debian Linux
  • Google Cloud Platform
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • Open Source Linux Kernel
  • RESF Rocky Linux
  • NetApp ActiveIQ Unified Manager
  • 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: 5.6
VulDB Meta Temp Score: 5.5

VulDB Base Score: 5.7
VulDB Temp Score: 5.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔒

CVSSv2info

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

Exploitinginfo

Class: Denial of service
CWE: CWE-404
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: 269453
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2025-39931

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.1.154/6.6.108/6.12.49/6.16.9
Patch: 6241b9e2809b12da9130894cf5beddf088dc1b8a/2374c11189ef704a3e4863646369f1b8e6a27d71/24c1106504c625fabd3b7229611af617b4c27ac7/045ee26aa3920a47ec46d7fcb302420bf01fd753/9574b2330dbd2b5459b74d3b5e9619d39299fc6f

Timelineinfo

04/16/2025 CVE reserved
10/04/2025 +171 days Advisory disclosed
10/04/2025 +0 days VulDB entry created
04/28/2026 +206 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2025-39931 (🔒)
GCVE (CVE): GCVE-0-2025-39931
GCVE (VulDB): GCVE-100-327021
CERT Bund: WID-SEC-2025-2194 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 10/04/2025 11:29
Updated: 04/28/2026 04:30
Changes: 10/04/2025 11:29 (59), 10/08/2025 18:45 (2), 11/24/2025 02:30 (7), 12/26/2025 23:04 (1), 01/27/2026 20:05 (10), 04/28/2026 04:30 (1)
Complete: 🔍
Cache ID: 216::103

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