CVE-2026-31611

HIGHPre-NVD 8.68.6—
EchelonGraph scoreMEDIUM confidence

Score 8.6 from GitHub Security Advisory (severity: HIGH) published 2026-04-24. the CNA's CVSS baseline 8.6; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:linux, epss, ghsa
8.6EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.6Exploit: 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:

ksmbd: require 3 sub-authorities before reading sub_auth[2]

parse_dacl() compares each ACE SID against sid_unix_NFS_mode and on match reads sid.sub_auth[2] as the file mode. If sid_unix_NFS_mode is the prefix S-1-5-88-3 with num_subauth = 2 then compare_sids() compares only min(num_subauth, 2) sub-authorities so a client SID with num_subauth = 2 and sub_auth = {88, 3} will match.

If num_subauth = 2 and the ACE is placed at the very end of the security descriptor, sub_auth[2] will be 4 bytes past end_of_acl. The out-of-band bytes will then be masked to the low 9 bits and applied as the file's POSIX mode, probably not something that is good to have happen.

Fix this up by forcing the SID to actually carry a third sub-authority before reading it at all.

CVSS v3
8.6
EG Score
8.6(medium)
EG Risk
43(Track)
EG Risk 43/100SSVC: 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
Severity86% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
30%
KEV
Not listed

Published

April 24, 2026

Last Modified

August 5, 2026

Advisory Details (6)

Auto-updated Apr 29, 2026
No patch confirmed yet.
generic

ksmbd: require 3 sub-authorities before reading sub_auth[2] - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/d2454f4a002d08560a60f214f392e6491cf11560
generic

ksmbd: require 3 sub-authorities before reading sub_auth[2] - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/b5b5d5936a50497fb151c0b122899a6894721c2b
generic

ksmbd: require 3 sub-authorities before reading sub_auth[2] - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/9401f86a224f37b50e6a3ccf1d46a70d5ef8af0a
generic

ksmbd: require 3 sub-authorities before reading sub_auth[2] - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/53370cf9090777774e07fd9a8ebce67c6cc333ab
generic

ksmbd: require 3 sub-authorities before reading sub_auth[2] - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/46bbcd3ebfb3549c8da1838fc4493e79bd3241e7
generic

ksmbd: require 3 sub-authorities before reading sub_auth[2] - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/08f9e6d899b5c834bbcc239eae1bed58d9b15d2c

Vendor Advisories for CVE-2026-31611(2)

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

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
linuxKernel @ 6.1.175—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

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
linux-6.16.1.106-3~deb11u1 ... 6.1.174-1~deb11u1 (20 versions)6.1.176-1~deb11u1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
linux6.1.106-1 ... 6.1.99-1 (53 versions)6.1.176-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
linux6.12.38-1 ... 6.12.85-1~bpo12+1 (17 versions)6.12.85-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
linux6.12.100-1 ... 6.19~rc8-1~exp1 (126 versions)6.19.14-1—

Additional Vendor Advisories

(18)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 8× in last 7d / 67× 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 252 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-31611?
CVE-2026-31611 is a high vulnerability published on April 24, 2026. In the Linux kernel, the following vulnerability has been resolved: ksmbd: require 3 sub-authorities before reading sub_auth[2] parsedacl() compares each ACE SID against sidunixNFSmode and on match reads sid.subauth[2] as the file mode. If sidunixNFSmode is the prefix S-1-5-88-3 with numsubauth = 2…
When was CVE-2026-31611 disclosed?
CVE-2026-31611 was first published in the National Vulnerability Database on April 24, 2026, with the most recent update on August 5, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-31611 actively exploited?
CVE-2026-31611 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 70.3% of all scored CVEs.
What is the CVSS score of CVE-2026-31611?
CVE-2026-31611 has a CVSS v4.0 base score of 8.6 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-31611?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-31611, 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-2026-31611

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