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[ CVE-2025-39964 · Published 13 Oct 2025 ]

Linux Kernel Race Condition Vulnerability

Exploited · CISA KEV CVSS 5.5 EPSS 1%5 agency advisoriesFix available

[ Why it matters ]Priority signals

  • Exploited in the wild: on CISA's Known Exploited Vulnerabilities list since 2026-09-18

[ Description ]Official 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: Linux Kernel contains a race condition vulnerability which allows concurrent writes to the same AF_ALG socket causing data to be unpredictably interleaved and creating inconsistencies in the socket's internal state.

[ Fixes ]Fixes and patches

CISA required action (US federal deadline 21 Sep 2026): 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.

[ Advisories ]Government CERT advisories

  • CERT-FRCERTFR-2026-AVI-1335

    Multiple vulnerabilities in the SUSE Linux kernel Translated from French

    Multiple vulnerabilities have been discovered in the SUSE Linux kernel. Some of them allow an attacker to cause privilege escalation, remote denial of service and a breach of data confidentiality.

    CVE-2026-72436CVE-2026-74632CVE-2026-89702+602 more CVEs
  • CERT-FRCERTFR-2026-AVI-1298

    Multiple vulnerabilities in Siemens products Translated from French

    Multiple vulnerabilities have been discovered in Siemens products. Some of them allow an attacker to cause remote arbitrary code execution, privilege escalation and remote denial of service.

    CVE-2021-41617CVE-2023-28531CVE-2023-51384+716 more CVEs
  • CERT-FRCERTFR-2026-AVI-1254

    Multiple vulnerabilities in the Red Hat Linux kernel Translated from French

    Multiple vulnerabilities have been discovered in the Red Hat Linux kernel. Some of them allow an attacker to cause arbitrary code execution, privilege escalation and remote denial of service.

    CVE-2026-46325CVE-2026-53091CVE-2026-68480+61 more CVEs
  • CERT-FRCERTFR-2026-AVI-1230

    Multiple vulnerabilities in the Red Hat Linux kernel Translated from French

    Multiple vulnerabilities have been discovered in the Red Hat Linux kernel. Some of them allow an attacker to cause remote arbitrary code execution, privilege escalation and remote denial of service.

    CVE-2026-31539CVE-2026-53002CVE-2026-64268+78 more CVEs
  • CERT-FRCERTFR-2026-AVI-1231

    Multiple vulnerabilities in the SUSE Linux kernel Translated from French

    Multiple vulnerabilities have been discovered in the SUSE Linux kernel. Some of them allow an attacker to cause arbitrary code execution, remote denial of service and a breach of data confidentiality.

    CVE-2026-31483CVE-2026-53091CVE-2026-53381+284 more CVEs

[ References ]References