CVE-2025-39964

CRITICALNVD 5.59.0▲
EchelonGraph scoreHIGH confidence

Score elevated to 9.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2026-09-18), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 5.5 retained for reference. Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: cisa_kev, epss, ghsa, nvd
Trending — KEV-added this weekExploited in the wild
9.0EG
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS PROB: 1%CVSS: 5.5Exploit: cisa kev · ssvc active · public exploitExposed: 0

A fix is available — apply it.

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.

CVSS v3
5.5
EG Score
9.0(high)
EG Risk
81(Attend)
EG Risk 81/100SSVC: Attend

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity90% × 45%
Exploitation100% × 40%
Automatability0% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
1%
EPSS %ILE
55%
KEV
⚠ Exploited

Published

October 13, 2025

Last Modified

September 19, 2026

Advisory Details (9)

Auto-updated Sep 18, 2026
⚠️ Active exploitation confirmed. Patch available. Sources: cisa.
cisa Patch Available🔴 Active Exploitation

Known Exploited Vulnerabilities Catalog | CISA

Known Exploited Vulnerabilities Catalog | CISA. Listed in CISA Known Exploited Vulnerabilities catalog.

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-39964
generic

SSA-019113

https://cert-portal.siemens.com/productcert/html/ssa-019113.html
generic

crypto: af_alg - Disallow concurrent writes in af_alg_sendmsg - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/e4c1ec11132ec466f7362a95f36a506ce4dc08c9
generic

crypto: af_alg - Disallow concurrent writes in af_alg_sendmsg - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/9aee87da5572b3a14075f501752e209801160d3d
generic

crypto: af_alg - Disallow concurrent writes in af_alg_sendmsg - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/7c4491b5644e3a3708f3dbd7591be0a570135b84
generic

crypto: af_alg - Disallow concurrent writes in af_alg_sendmsg - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/45bcf60fe49b37daab1acee57b27211ad1574042
generic

crypto: af_alg - Disallow concurrent writes in af_alg_sendmsg - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/1f323a48e9b5ebfe6dc7d130fdf5c3c0e92a07c8
generic

crypto: af_alg - Disallow concurrent writes in af_alg_sendmsg - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/1b34cbbf4f011a121ef7b2d7d6e6920a036d5285
generic

crypto: af_alg - Disallow concurrent writes in af_alg_sendmsg - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/0f28c4adbc4a97437874c9b669fd7958a8c6d6ce

Vendor Advisories for CVE-2025-39964(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(31)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-xilinx-zynqmp (6.8.0.1021.22) @ noble2026-09-20ubuntu
ubuntulinux-tools-iot-5.4 (5.4.0.1057.55) @ focal2026-09-20ubuntu
ubuntulinux-xilinx-zynqmp-tools-5.4.0-1071 (5.4.0-1071.75) @ focal2026-09-20ubuntu
ubuntulinux-tools-gcp-fips-5.4 (5.4.0.1156.98) @ focal2026-09-20ubuntu
ubuntulinux-tools-realtime-5.15 (5.15.0.1097.101) @ jammy2026-09-20ubuntu
ubuntulinux-tools-realtime-6.8.1 (6.8.1-1039.40) @ noble2026-09-20ubuntu
ubuntulinux-tools-gcp-fips-6.8 (6.8.0-1045.48+fips1) @ noble2026-09-20ubuntu
ubuntulinux-virtual-lts-xenial (4.4.0.276.282) @ xenial2026-09-20ubuntu
ubuntulinux-tools-azure-6.14 (6.14.0-1017.17) @ plucky2026-09-20ubuntu
ubuntulinux-tools-azure-lts-24.04 (6.8.0-1044.50) @ noble2026-09-20ubuntu
ubuntulinux-tools-oem-6.14 (6.14.0-1017.17) @ noble2026-09-20ubuntu
ubuntulinux-tools-azure-edge (5.15.0.1102.111~20.04.1) @ focal2026-09-20ubuntu
ubuntulinux-tools-azure-lts-20.04 (5.4.0.1156.150) @ focal2026-09-20ubuntu
ubuntulinux-tools-raspi2-hwe-18.04-edge (5.4.0.1136.167) @ focal2026-09-20ubuntu
ubuntulinux-tools-raspi-nolpae (5.15.0.1092.90) @ jammy2026-09-20ubuntu
ubuntulinux-tools-kvm-5.15 (5.15.0.1090.86) @ jammy2026-09-20ubuntu
ubuntulinux-virtual-hwe-24.04-edge (6.14.0-37.37) @ plucky2026-09-20ubuntu
ubuntulinux-xilinx-zynqmp-tools-5.15.0-1062 (5.15.0-1062.66) @ jammy2026-09-20ubuntu
ubuntulinux-tools-gcp-fips-5.15 (5.15.0.1098.88) @ jammy2026-09-20ubuntu
ubuntulinux-tools-oracle (4.15.0.1149.160~16.04.1) @ xenial2026-09-20ubuntu
ubuntulinux-virtual-6.8 (6.8.0-90.91) @ noble2026-09-20ubuntu
ubuntulinux-tools-azure-fips-5.4 (5.4.0.1157.94) @ focal2026-09-20ubuntu
ubuntulinux-tools-azure-fips-6.8 (6.8.0-1044.50+fips1) @ noble2026-09-20ubuntu
ubuntulinux-tools-oracle-edge (5.4.0.1151.161~18.04.1) @ bionic2026-09-20ubuntu
ubuntulinux-tools-realtime-hwe-24.04 (6.14.0-1017.17~24.04.1) @ noble2026-09-20ubuntu
ubuntulinux-tools-raspi-realtime-6.8 (6.8.0-2035.36) @ noble2026-09-20ubuntu
ubuntulinux-tools-aws-hwe (4.15.0.1187.200~16.04.1) @ xenial2026-09-20ubuntu
ubuntulinux-tools-fips (4.15.0.1142.139) @ bionic2026-09-20ubuntu
ubuntulinux-virtual-hwe-16.04-edge (4.15.0.245.257~16.04.1) @ xenial2026-09-20ubuntu
ubuntulinux-tools-gcp-fips-4.15 (4.15.0.2088.86) @ bionic2026-09-20ubuntu
linuxKernel @ 5.10.245—osv

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(5 across 4 ecosystems)
Debian:11(2)
PackageVulnerable rangeFixed inDependents
linux5.10.103-1 ... 5.10.92-2 (47 versions)5.10.247-1—
linux-6.16.1.106-3~deb11u1 ... 6.1.153-1~deb11u1 (12 versions)6.1.158-1~deb11u1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
linux6.1.106-1 ... 6.1.99-1 (44 versions)6.1.158-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
linux6.12.38-1 ... 6.12.57-1~bpo12+1 (6 versions)6.12.57-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
linux6.12.100-1 ... 6.16~rc7-1~exp1 (67 versions)6.16.9-1—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

All Vendor Advisories

(25)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 55× in last 7d / 79× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 205 total refreshes for this CVE.

  1. 2026-09-20 16:58 UTCVendor advisory
  2. 2026-09-20 16:57 UTCGHSA enrichment
  3. 2026-09-20 12:56 UTCVendor advisory
  4. 2026-09-20 12:56 UTCGHSA enrichment
  5. 2026-09-20 08:51 UTCVendor advisory
  6. 2026-09-20 08:51 UTCGHSA enrichment
  7. 2026-09-20 04:50 UTCVendor advisory
  8. 2026-09-20 04:49 UTCGHSA enrichment
  9. 2026-09-20 00:48 UTCVendor advisory
  10. 2026-09-20 00:47 UTCGHSA enrichment
  11. 2026-09-19 20:46 UTCVendor advisory
  12. 2026-09-19 20:45 UTCGHSA enrichment
  13. 2026-09-19 16:43 UTCEG score recompute
  14. 2026-09-19 16:43 UTCVendor advisory
  15. 2026-09-19 16:43 UTCGHSA enrichment
  16. 2026-09-19 12:42 UTCVendor advisory
  17. 2026-09-19 12:42 UTCGHSA enrichment
  18. 2026-09-19 08:41 UTCVendor advisory
  19. 2026-09-19 08:39 UTCGHSA enrichment
  20. 2026-09-19 08:37 UTCGHSA enrichment
  21. 2026-09-19 08:35 UTCGHSA enrichment
  22. 2026-09-19 08:33 UTCGHSA enrichment
  23. 2026-09-19 04:31 UTCVendor advisory
  24. 2026-09-19 04:30 UTCGHSA enrichment
  25. 2026-09-19 04:01 UTCVendor advisory
Show 75 more
  1. 2026-09-19 04:01 UTCGHSA enrichment
  2. 2026-09-19 02:56 UTCVendor advisory
  3. 2026-09-19 02:55 UTCGHSA enrichment
  4. 2026-09-18 22:54 UTCEG score recompute
  5. 2026-09-18 22:54 UTCVendor advisory
  6. 2026-09-18 22:53 UTCGHSA enrichment
  7. 2026-09-18 19:27 UTCEPSS rescore
  8. 2026-09-18 19:20 UTCCISA KEV update
  9. 2026-09-18 18:52 UTCEG score recompute
  10. 2026-09-18 18:52 UTCVendor advisory
  11. 2026-09-18 18:52 UTCGHSA enrichment
  12. 2026-09-18 18:51 UTCNVD updateCVSS v3 → 5.5 · severity → MEDIUM
  13. 2026-09-18 15:23 UTCEG score recompute
  14. 2026-09-18 15:23 UTCVendor advisory
  15. 2026-09-18 15:23 UTCGHSA enrichment
  16. 2026-09-18 14:44 UTCEG score recompute
  17. 2026-09-18 14:44 UTCVendor advisory
  18. 2026-09-18 14:44 UTCGHSA enrichment
  19. 2026-09-18 14:15 UTCEG score recompute▲ 5.70
  20. 2026-09-18 14:15 UTCVendor advisory
  21. 2026-09-18 14:15 UTCGHSA enrichment
  22. 2026-09-18 14:15 UTCCISA KEV update
  23. 2026-09-18 13:19 UTCVendor advisory
  24. 2026-09-18 13:18 UTCGHSA enrichment
  25. 2026-09-18 13:14 UTCEG score recompute
  26. 2026-09-18 13:14 UTCVendor advisory
  27. 2026-09-18 13:14 UTCGHSA enrichment
  28. 2026-09-17 19:29 UTCEPSS rescore
  29. 2026-09-16 14:07 UTCEPSS rescore
  30. 2026-09-16 05:14 UTCEPSS rescore
  31. 2026-09-13 16:46 UTCEPSS rescore
  32. 2026-09-12 15:00 UTCEPSS rescore
  33. 2026-09-11 14:52 UTCEPSS rescore
  34. 2026-09-11 09:35 UTCEPSS rescore
  35. 2026-09-10 09:33 UTCEPSS rescore
  36. 2026-09-08 21:59 UTCEPSS rescore
  37. 2026-09-08 09:48 UTCEG score recompute
  38. 2026-09-08 09:48 UTCVendor advisory
  39. 2026-09-08 09:48 UTCGHSA enrichment
  40. 2026-09-07 16:00 UTCEPSS rescore
  41. 2026-09-07 11:18 UTCOSV refresh
  42. 2026-09-06 13:46 UTCEPSS rescore
  43. 2026-09-04 05:05 UTCEPSS rescore
  44. 2026-09-02 14:11 UTCEPSS rescore
  45. 2026-09-01 13:53 UTCEPSS rescore
  46. 2026-09-01 04:38 UTCEPSS rescore
  47. 2026-08-30 19:16 UTCEPSS rescore
  48. 2026-08-30 01:21 UTCEPSS rescore
  49. 2026-08-28 21:40 UTCEPSS rescore
  50. 2026-08-27 14:24 UTCEPSS rescore
  51. 2026-08-26 14:45 UTCEPSS rescore
  52. 2026-08-25 13:48 UTCEPSS rescore
  53. 2026-08-23 00:18 UTCEPSS rescore
  54. 2026-08-21 23:48 UTCEPSS rescore
  55. 2026-08-20 22:54 UTCEPSS rescore
  56. 2026-08-20 20:31 UTCOSV refresh
  57. 2026-08-19 17:03 UTCEPSS rescore
  58. 2026-08-19 17:03 UTCEPSS rescore
  59. 2026-08-18 13:47 UTCEPSS rescore
  60. 2026-08-17 13:46 UTCEPSS rescore
  61. 2026-08-16 14:55 UTCEPSS rescore
  62. 2026-08-16 02:13 UTCEPSS rescore
  63. 2026-08-15 01:29 UTCEPSS rescore
  64. 2026-08-13 21:59 UTCEPSS rescore
  65. 2026-08-12 13:50 UTCEPSS rescore
  66. 2026-08-09 13:46 UTCEPSS rescore
  67. 2026-08-08 16:36 UTCEPSS rescore
  68. 2026-08-07 16:26 UTCEPSS rescore
  69. 2026-08-06 13:46 UTCEPSS rescore
  70. 2026-08-05 12:55 UTCEG score recompute
  71. 2026-08-05 12:55 UTCVendor advisory
  72. 2026-08-05 12:55 UTCGHSA enrichment
  73. 2026-08-04 15:09 UTCEPSS rescore
  74. 2026-08-04 10:37 UTCEPSS rescore
  75. 2026-08-03 10:35 UTCEPSS rescore

Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 GitHub PoC). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCn1k0oowang/CVE-2025-39964_EXP
    First seen Nov 13, 2025

    CVE-2025-39964 EXP

    Open source ↗

Related CVEs(same product + same vendor + same CWE)

Frequently asked(6)

What is CVE-2025-39964?
CVE-2025-39964 is a critical vulnerability published on October 13, 2025. In the Linux kernel, the following vulnerability has been resolved: crypto: afalg - Disallow concurrent writes in afalg_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…
When was CVE-2025-39964 disclosed?
CVE-2025-39964 was first published in the National Vulnerability Database on October 13, 2025, with the most recent update on September 19, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2025-39964 actively exploited?
Yes. CISA added CVE-2025-39964 to the Known Exploited Vulnerabilities catalog on September 18, 2026, affecting Linux Kernel. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2025-39964?
CVE-2025-39964 has a CVSS v3 base score of 5.5 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0.
Which products are affected by CVE-2025-39964?
CVE-2025-39964 affects Linux Kernel. The full affected-products list, including version ranges and fixed versions, is shown in the Affected Packages section of this page.
How do I remediate CVE-2025-39964?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-39964, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2025-39964

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