VULNpocalypse

CVE-2025-39964: Linux Kernel Race Condition Vulnerability

Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.

Generated by VEDAS. Scores as of 2026-11-01 19:19 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.

What it is

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.

Description quoted from the CVE record (assigned by Linux, published 2025-10-13).

Weakness: CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization (‘Race Condition’)

How it can be exploited

Exploitable with local access with low attack complexity needing low privileges and no user interaction. Impact: confidentiality high, integrity high, availability high. CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CISA assessment (SSVC): CISA assesses exploitation as active. Automatable: no. Technical impact: total.

On CISA KEV since
2026-09-18
US federal deadline
2026-09-21
Ransomware use
Not known

Public exploit evidence (Exploit Observer)

Also known as: BDU:2025-16058, CNNVD-202510-1667, EUVD-2025-34068, GHSA-wr5g-mfhw-rpfj, SNYK-AMZN2023-KERNEL612MODULESEXTRACOMMON-13731558, SNYK-AMZN2023-PERF612DEBUGINFO-13731554, SNYK-RHEL10-KERNELHEADERS-13542611

VEDAS cluster: VEDAS:BEGUILINGBEHEMOTH

Exploit Observer links 2 pieces of public exploit code or detection modules that name this CVE or one of its aliases.

Exploit code and modules (2)

Code that names this CVE. A repository can be a working exploit, a scanner, a fake or malware; read it before running anything.

Research and write-ups (1)

Vulnerability databases and vendor advisories (18)

Catalogue entries, not exploit evidence.

136 more references returned by Exploit Observer did not name this CVE or an alias, so they are left out.

VEDAS data as of 2026-11-01T17:12 UTC; fetched 2026-11-02.

Live scores

EPSS
0.016
some chance of attack soon
VEDAS
0.972
strong exploit evidence
On CISA KEV
Yes, since 2026-09-18
Detection rule
None yet
EPSS (chance of attack)
10No cve-scores data 2026-02-22 to 2026-08-08no data0.1Added to CISA KEV 2026-09-18CVE-2025-39964 EPSS over time2025-102026-11-01
VEDAS (exploit evidence)
10No cve-scores data 2026-02-22 to 2026-08-08no data0.9Added to CISA KEV 2026-09-18CVE-2025-39964 VEDAS over time2025-102026-11-01

Thin horizontal line: the “likely” (EPSS 0.10) or “strong” (VEDAS 0.90) threshold. Shaded “no data” areas are periods when cve-scores did not publish. The vertical line is the day CISA added it to its exploited list.

VEDAS flagged this bug about 20 days before CISA confirmed attacks.

Who is affected

ProductAffectedNot affected
Linux Linuxfrom 8ff590903d5f before 0f28c4adbc4a (git commit)
from 8ff590903d5f before e4c1ec11132e (git commit)
from 8ff590903d5f before 1f323a48e9b5 (git commit)
from 8ff590903d5f before 7c4491b5644e (git commit)
from 8ff590903d5f before 9aee87da5572 (git commit)
from 8ff590903d5f before 45bcf60fe49b (git commit)
from 8ff590903d5f before 1b34cbbf4f01 (git commit)		Not stated
Linux Linuxversion 2.6.380 is not affected (up to 2.6.38); 5.10.245 is not affected; 5.15.194 is not affected; 6.1.154 is not affected

Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.

Exploit Observer also maps it to: linux linux_kernel, ооо_«ред_софт» ред_ос, ооо_«русбитех-астра» astra_linux_special_edition, сообщество_свободного_программного_обеспечения linux.

How to fix it

CISA required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset’s internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Vendor guidance:

How to detect it

There is no open VEDAS detection rule for this bug yet. It is listed on the detection gaps page if CISA has confirmed attacks.

References

Government sources

Other references

Other databases

Where this comes from

This advisory is generated automatically by VEDAS from: CVE.org record, CISA KEV, cve-scores (EPSS and VEDAS), Exploit Observer. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.