crypto: af_alg - Disallow concurrent writes in af_alg_sendmsg

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2025-39964
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2025-10-13 14:15:34 UTC
Updated2026-10-19 21:10:00 UTC
DescriptionIn 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.

Risk And Classification

Primary CVSS: v3.1 5.5 MEDIUM from [email protected]

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS: 0.015700000 probability, percentile 0.751930000 (date 2026-10-25)

CISA KEV: Listed on 2026-09-18; due 2026-09-21; ransomware use Unknown

Problem Types: CWE-362 | CWE-362 CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary5.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CISA Known Exploited Vulnerability

VendorLinux
ProductKernel
NameLinux Kernel Race Condition Vulnerability
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.
NotesThis vulnerability affects an open-source component, third-party library, protocol, or proprietary implementation that could be used by different products. For more information, please see: ; https://git.kernel.org/stable/c/0f28c4adbc4a97437874c9b669fd7958a8c6d6ce; https://git.kernel.org/stable/c/e4c1ec11132ec466f7362a95f36a506ce4dc08c9; https://git.kernel.org/stable/c/1f323a48e9b5ebfe6dc7d130fdf5c3c0e92a07c8; https://git.kernel.org/stable/c/7c4491b5644e3a3708f3dbd7591be0a570135b84; https://git.kernel.org/stable/c/9aee87da5572b3a14075f501752e209801160d3d; https://git.kernel.org/stable/c/45bcf60fe49b37daab1acee57b27211ad1574042; https://git.kernel.org/stable/c/1b34cbbf4f011a121ef7b2d7d6e6920a036d5285 ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2025-39964

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Linux Linux Kernel All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 0f28c4adbc4a97437874c9b669fd7958a8c6d6ce git Not specified
CNA Linux Linux affected 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 e4c1ec11132ec466f7362a95f36a506ce4dc08c9 git Not specified
CNA Linux Linux affected 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 1f323a48e9b5ebfe6dc7d130fdf5c3c0e92a07c8 git Not specified
CNA Linux Linux affected 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 7c4491b5644e3a3708f3dbd7591be0a570135b84 git Not specified
CNA Linux Linux affected 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 9aee87da5572b3a14075f501752e209801160d3d git Not specified
CNA Linux Linux affected 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 45bcf60fe49b37daab1acee57b27211ad1574042 git Not specified
CNA Linux Linux affected 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 1b34cbbf4f011a121ef7b2d7d6e6920a036d5285 git Not specified
CNA Linux Linux affected 2.6.38 Not specified
CNA Linux Linux unaffected 2.6.38 semver Not specified
CNA Linux Linux unaffected 5.10.245 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.194 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.154 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.108 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.49 6.12.* semver Not specified
CNA Linux Linux unaffected 6.16.9 6.16.* semver Not specified
CNA Linux Linux unaffected 6.17 * original_commit_for_fix Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.6 * custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.7 * custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.6 * custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.7 * custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP affected V3.1.6 * custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP affected V3.1.7 * custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP affected V3.1.6 * custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP affected V3.1.7 * custom Not specified
ADP Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.6 * custom Not specified
ADP Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.7 * custom Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/7c4491b5644e3a3708f3dbd7591be0a570135b84 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
cert-portal.siemens.com/productcert/html/ssa-457936.html 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e cert-portal.siemens.com Third Party Advisory
git.kernel.org/stable/c/45bcf60fe49b37daab1acee57b27211ad1574042 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
cert-portal.siemens.com/productcert/html/ssa-019113.html 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e cert-portal.siemens.com Third Party Advisory
git.kernel.org/stable/c/1b34cbbf4f011a121ef7b2d7d6e6920a036d5285 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/e4c1ec11132ec466f7362a95f36a506ce4dc08c9 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/1f323a48e9b5ebfe6dc7d130fdf5c3c0e92a07c8 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/9aee87da5572b3a14075f501752e209801160d3d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
www.cisa.gov/known-exploited-vulnerabilities-catalog 134c704f-9b21-4f2e-91b3-4a467353bcc0 www.cisa.gov US Government Resource
git.kernel.org/stable/c/0f28c4adbc4a97437874c9b669fd7958a8c6d6ce 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis
CISA Known Exploited Vulnerabilities catalog CISA www.cisa.gov kev

Additional Advisory Data

SourceTimeEvent
ADP2026-09-18T00:00:00.000ZCVE-2025-39964 added to CISA KEV

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