Oct 19, 2026 · 13:51 UTC SEARCH
UNRATED KNOWN EXPLOITED
Vulnerability intelligence

CVE-2025-39964

VendorLinux
ProductKernel
Known exploitedYes
Added to CISA KEVSeptember 18, 2026
KEV due dateSeptember 21, 2026
Known ransomware useNot identified by 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.

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.

CISA KEV status

This vulnerability is listed in CISA’s Known Exploited Vulnerabilities Catalog. Known ransomware campaign use: Unknown.

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