CVE-2025-39964

medium

Description

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.

References

https://cert-portal.siemens.com/productcert/html/ssa-019113.html

https://www.securityweek.com/organizations-warned-of-3-exploited-linux-kernel-vulnerabilities/

https://www.bleepingcomputer.com/news/security/cisa-alerts-of-active-exploitation-of-three-linux-kernel-flaws/

https://securityaffairs.com/199430/security/u-s-cisa-adds-linux-kernel-flaws-to-its-known-exploited-vulnerabilities-catalog-2.html

https://thehackernews.com/2026/09/cisa-flags-three-linux-kernel.html

https://www.cisa.gov/news-events/alerts/2026/09/18/cisa-adds-two-known-exploited-vulnerabilities-catalog

https://docs.cloud.google.com/support/bulletins/index#gcp-2026-003

https://github.com/suominen/CVE-2025-39964

https://github.com/n1k0oowang/CVE-2025-39964_EXP

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-39964

https://git.kernel.org/stable/c/e4c1ec11132ec466f7362a95f36a506ce4dc08c9

https://git.kernel.org/stable/c/9aee87da5572b3a14075f501752e209801160d3d

https://git.kernel.org/stable/c/7c4491b5644e3a3708f3dbd7591be0a570135b84

https://git.kernel.org/stable/c/45bcf60fe49b37daab1acee57b27211ad1574042

https://git.kernel.org/stable/c/1f323a48e9b5ebfe6dc7d130fdf5c3c0e92a07c8

https://git.kernel.org/stable/c/1b34cbbf4f011a121ef7b2d7d6e6920a036d5285

https://git.kernel.org/stable/c/0f28c4adbc4a97437874c9b669fd7958a8c6d6ce

https://euvd.enisa.europa.eu/vulnerability/EUVD-2025-34068

Details

Source: Mitre, NVD

Published: 2025-10-13

Updated: 2026-09-19

Named Vulnerability: GHSA-wr5g-mfhw-rpfjKnown Exploited Vulnerability (KEV)

Risk Information

CVSS v2

Base Score: 4.6

Vector: CVSS2#AV:L/AC:L/Au:S/C:N/I:N/A:C

Severity: Medium

CVSS v3

Base Score: 5.5

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Severity: Medium

EPSS

EPSS: 0.01276