CVE-2026-64380

HIGHPre-NVD 8.28.2—
EchelonGraph scoreMEDIUM confidence

Score 8.2 from GitHub Security Advisory (severity: HIGH) published 2026-07-25. a secondary CVSS source baseline 8.2; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
8.2EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.2Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

In the Linux kernel, the following vulnerability has been resolved:

smb: client: harden POSIX SID length parsing

posix_info_sid_size() reads sid[1] to obtain the subauthority count, but its existing boundary check still accepts buffers with only one remaining byte. Require two bytes before reading sid[1] so all client paths that reuse the helper reject truncated POSIX SIDs safely.

CVSS v3
8.2
EG Score
8.2(medium)
EG Risk
42(Track)
EG Risk 42/100SSVC: Track

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
Severity82% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
37%
KEV
Not listed

Published

July 25, 2026

Last Modified

August 17, 2026

Advisory Details (8)

Auto-updated Jul 27, 2026
No patch confirmed yet.
generic

smb: client: harden POSIX SID length parsing - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/96e889bc1e759c83f25093e8c2f3da31b4973f30
generic

smb: client: harden POSIX SID length parsing - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/86c5d470f5d42e61123b2f4b4f0b91f4eee5b980
generic

smb: client: harden POSIX SID length parsing - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/7ad2bcf2441430bb2e918fb3ef9a90d775a6e422
generic

smb: client: harden POSIX SID length parsing - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/46a84715a015cb48e1b9c219dc88c03d8a541ea4
generic

smb: client: harden POSIX SID length parsing - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/427eb7eb46425fec845a43e861f3d6e2899cae59
generic

smb: client: harden POSIX SID length parsing - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/4213c1208978483021d7d125c131de3985d38f61
generic

smb: client: harden POSIX SID length parsing - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/171605aed68380c2fa75dff9b3a1ed427c50065b
generic

smb: client: harden POSIX SID length parsing - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/0de5b8e76847f5de26f364a82c6602c4881c30da

Vendor Advisories for CVE-2026-64380(2)

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

Affected Packages

(6 across 4 ecosystems)
Debian:11(2)
PackageVulnerable rangeFixed inDependents
linux5.10.103-1 ... 5.10.92-2 (55 versions)5.10.262-1—
linux-6.16.1.106-3~deb11u1 ... 6.1.177-1~deb11u1 (22 versions)6.1.180-1~deb11u1—
Debian:12(2)
PackageVulnerable rangeFixed inDependents
linux6.1.106-1 ... 6.1.99-1 (55 versions)6.1.180-1—
linux-6.12—6.12.100-1~deb12u1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
linux6.12.38-1 ... 6.12.95-1~bpo12+1 (30 versions)6.12.96-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
linux6.12.100-1 ... 7.1~rc7-1~exp1 (156 versions)7.1.4-1—

Data Freshness Timeline

(refreshed 32× in last 7d / 157× 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 186 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-64380?
CVE-2026-64380 is a high vulnerability published on July 25, 2026. In the Linux kernel, the following vulnerability has been resolved: smb: client: harden POSIX SID length parsing posixinfosid_size() reads sid[1] to obtain the subauthority count, but its existing boundary check still accepts buffers with only one remaining byte. Require two bytes before reading…
When was CVE-2026-64380 disclosed?
CVE-2026-64380 was first published in the National Vulnerability Database on July 25, 2026, with the most recent update on August 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-64380 actively exploited?
CVE-2026-64380 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 63.1% of all scored CVEs.
What is the CVSS score of CVE-2026-64380?
CVE-2026-64380 has a CVSS v3 base score of 8.2 (NVD).
How do I remediate CVE-2026-64380?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-64380, 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-2026-64380

Explore →

Is Your Infrastructure Affected by CVE-2026-64380?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs