CVE-2025-39964
crypto: af_alg - Disallow concurrent writes in af_alg_sendmsg
- Published
- Oct 13, 2025
- Updated
- Sep 19, 2026
- Assigning CNA
- Linux
- Evidence observed
- Aug 8, 2026
Primary CVSS
nvd · CVSS 3.1
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HLow · next 30 days
- Percentile
- 54.3%
- Model date
- Sep 21, 2026
EPSS is a statistical estimate, not a certainty or a measure of impact. Combine it with CVSS, KEV status, exposure and your environment.
CISA Known Exploited
This CVE appears in the CISA Known Exploited Vulnerabilities catalog.
Summary
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.
Sources
2- CVE-2025-39964Informational
Patch-status tracker for CVE-2025-39964, a Linux AF_ALG race condition enabling local privilege escalation, recording per-distribution fix availability.
- CVE-2025-39964_EXPExploit
CVE-2025-39964 EXP
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