CVE-2025-39964 Affecting linux-6.1 package, versions <6.1.158-1~deb11u1


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.06% (19th percentile)

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  • Snyk IDSNYK-DEBIAN11-LINUX61-14114839
  • published26 Nov 2025
  • disclosed13 Oct 2025

Introduced: 13 Oct 2025

CVE-2025-39964  (opens in a new tab)

How to fix?

Upgrade Debian:11 linux-6.1 to version 6.1.158-1~deb11u1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream linux-6.1 package and not the linux-6.1 package as distributed by Debian. See How to fix? for Debian:11 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

crypto: af_alg - Disallow concurrent writes in af_alg_sendmsg

Issuing two writes to the same af_alg socket is bogus as the data will be interleaved in an unpredictable fashion. Furthermore, concurrent writes may create inconsistencies in the internal socket state.

Disallow this by adding a new ctx->write field that indiciates exclusive ownership for writing.

CVSS Base Scores

version 3.1