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CVE-2025-39964

Linux Kernel Race Condition Vulnerability

Linux KernelOperating systems
Open in ThreatlineRecord JSON
CVSS
7.8High
ExploitationExploited in the wildAdded to KEV 18 Sep 2026CISA KEV
Exploit odds (EPSS)1.36%Chance of exploitation activity in the next 30 days, higher than 71% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in0f28c4adbc4a97437874c9b669fd7958a8c6d6ceAlso 1f323a48e9b5ebfe6dc7d130fdf5c3c0e92a07c8, 7c4491b5644e3a3708f3dbd7591be0a570135b84 and 3 moreCVE List
Federal deadline21 Sep 2026Remediation due date for US federal agenciesCISA KEV
CISA required actionApply 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
Patching is not enoughCISA requires federal agencies to look for signs of compromise on affected systems, not only patch (forensic triage under BOD 26-04). Treat exposed systems as possibly compromised. CISA guidance

What fixes it

  • 0f28c4adbc4a97437874c9b669fd7958a8c6d6ceLinuxCVE List
  • 1f323a48e9b5ebfe6dc7d130fdf5c3c0e92a07c8LinuxCVE List
  • 7c4491b5644e3a3708f3dbd7591be0a570135b84LinuxCVE List
  • 9aee87da5572b3a14075f501752e209801160d3dLinuxCVE List
  • 45bcf60fe49b37daab1acee57b27211ad1574042LinuxCVE List
  • 1b34cbbf4f011a121ef7b2d7d6e6920a036d5285LinuxCVE List

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

Timeline

  1. 13 Oct 2025, 13:48 UTCPublishedCVE List
  2. 18 Sep 2026Added to CISA KEVCISA KEV

Description

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.

Text from CVE List

Affected versions 16

  • Linuxaffected: 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 before 0f28c4adbc4a97437874c9b669fd7958a8c6d6ceCVE List
  • Linuxaffected: 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 before e4c1ec11132ec466f7362a95f36a506ce4dc08c9CVE List
  • Linuxaffected: 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 before 1f323a48e9b5ebfe6dc7d130fdf5c3c0e92a07c8CVE List
  • Linuxaffected: 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 before 7c4491b5644e3a3708f3dbd7591be0a570135b84CVE List
  • Linuxaffected: 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 before 9aee87da5572b3a14075f501752e209801160d3dCVE List
  • Linuxaffected: 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 before 45bcf60fe49b37daab1acee57b27211ad1574042CVE List
  • Linuxaffected: 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 before 1b34cbbf4f011a121ef7b2d7d6e6920a036d5285CVE List
  • Linuxaffected: 2.6.38CVE List
  • Linuxunaffected: all versions before 2.6.38CVE List
  • Linuxunaffected: 5.10.245 through 5.10.*CVE List
  • Linuxunaffected: 5.15.194 through 5.15.*CVE List
  • Linuxunaffected: 6.1.154 through 6.1.*CVE List
  • Linuxunaffected: 6.6.108 through 6.6.*CVE List
  • Linuxunaffected: 6.12.49 through 6.12.*CVE List
  • Linuxunaffected: 6.16.9 through 6.16.*CVE List
  • Linuxunaffected: 6.17CVE List

References 11