CVE-2025-39964
CVSS v3
3.3
LOW
EPSS Score
0.0 %
exploit probability
CISA KEV
Yes
known exploited
Exploitation
—
SSVC status
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.
CISA Known Exploited Vulnerability
- Date Added
- 2026-09-18
- Patch Due Date
- 2026-09-21
- Ransomware Use
- Unknown
Technical details
- Published
- 2025-10-13
Frequently asked questions
What is CVE-2025-39964?
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.
Is CVE-2025-39964 actively exploited?
Yes. CVE-2025-39964 is on the CISA Known Exploited Vulnerabilities (KEV) catalog, meaning it has been confirmed as actively exploited in the wild. CISA requires federal agencies to patch by 2026-09-21.
What is the CVSS score for CVE-2025-39964?
CVE-2025-39964 has a CVSS v3 base score of 3.3 (LOW severity).
Is CVE-2025-39964 affecting your environment?
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