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CVE-2025-39931
crypto: af_alg - Set merge to zero early in af_alg_sendmsg
Description

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.

INFO

Published Date :

Oct. 4, 2025, 8:15 a.m.

Last Modified :

Oct. 6, 2025, 2:56 p.m.

Remotely Exploit :

No

Source :

416baaa9-dc9f-4396-8d5f-8c081fb06d67
Affected Products

The following products are affected by CVE-2025-39931 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Linux linux_kernel
: Total Affected Vendor : 1 | Products : 1
Solution
Set the merge field to zero early in af_alg_sendmsg to prevent crashes.
  • Apply kernel patch to set ctx->merge to zero.
  • Update the Linux kernel to the latest version.
  • Ensure proper error handling in af_alg_sendmsg.
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2025-39931.

URL Resource
https://git.kernel.org/stable/c/045ee26aa3920a47ec46d7fcb302420bf01fd753
https://git.kernel.org/stable/c/2374c11189ef704a3e4863646369f1b8e6a27d71
https://git.kernel.org/stable/c/24c1106504c625fabd3b7229611af617b4c27ac7
https://git.kernel.org/stable/c/6241b9e2809b12da9130894cf5beddf088dc1b8a
https://git.kernel.org/stable/c/9574b2330dbd2b5459b74d3b5e9619d39299fc6f
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2025-39931 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2025-39931 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2025-39931 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2025-39931 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Oct. 04, 2025

    Action Type Old Value New Value
    Added Description 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.
    Added Reference https://git.kernel.org/stable/c/045ee26aa3920a47ec46d7fcb302420bf01fd753
    Added Reference https://git.kernel.org/stable/c/2374c11189ef704a3e4863646369f1b8e6a27d71
    Added Reference https://git.kernel.org/stable/c/24c1106504c625fabd3b7229611af617b4c27ac7
    Added Reference https://git.kernel.org/stable/c/6241b9e2809b12da9130894cf5beddf088dc1b8a
    Added Reference https://git.kernel.org/stable/c/9574b2330dbd2b5459b74d3b5e9619d39299fc6f
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
No CVSS metrics available for this vulnerability.