# CVE-2025-39931

## Summary

- **CVE ID:** CVE-2025-39931
- **Severity:** HIGH
- **CVSS Score:** 7.8 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
- **CWE:** N/A
- **Published:** Oct 4, 2025
- **Last Modified:** Sep 8, 2026

## 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.

## Affected Products

- Linux — Linux (8ff590903d5fc7f5a0a988c38267a3d08e6393a2)
- Linux — Linux (2.6.38)
- Linux — Linux (0)
- Linux — Linux (6.1.154)
- Linux — Linux (6.6.108)
- Linux — Linux (6.12.49)
- Linux — Linux (6.16.9)
- Linux — Linux (6.17)
- Linux — Linux (5.10.260)
- Linux — Linux (5.15.211)

## References

- [CNA](https://git.kernel.org/stable/c/6241b9e2809b12da9130894cf5beddf088dc1b8a)
- [CNA](https://git.kernel.org/stable/c/2374c11189ef704a3e4863646369f1b8e6a27d71)
- [CNA](https://git.kernel.org/stable/c/24c1106504c625fabd3b7229611af617b4c27ac7)
- [CNA](https://git.kernel.org/stable/c/045ee26aa3920a47ec46d7fcb302420bf01fd753)
- [CNA](https://git.kernel.org/stable/c/9574b2330dbd2b5459b74d3b5e9619d39299fc6f)
- [siemens-SADP](https://cert-portal.siemens.com/productcert/html/ssa-082556.html)
- [CNA](https://git.kernel.org/stable/c/28f6f37abca7c5c9eb3959c66310f1d4d98b8aaf)
- [CNA](https://git.kernel.org/stable/c/db2b42425dfbde4983b0c20fb7cfa05f70e6a745)
- [siemens-SADP](https://cert-portal.siemens.com/productcert/html/ssa-019113.html)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.16%
- **EPSS Percentile:** 5.7

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-17._