CVE-2026-64138

HIGHPre-NVD 8.88.8—
EchelonGraph scoreHIGH confidence

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2026-07-19. a secondary CVSS source baseline 8.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 5 sources updated this week
8.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.8Exploit: None knownExposed: 0

A fix is available — apply it.

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

ksmbd: validate SID in parent security descriptor during ACL inheritance

Introduce smb_validate_ntsd_sid() helper to safely validate Owner SID and Group SID inside the NT Security Descriptor (smb_ntsd) retrieved from the parent directory.

CVSS v3
8.8
EG Score
8.8(high)
EG Risk
44(Track)
EG Risk 44/100SSVC: 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
Severity88% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
34%
KEV
Not listed

Published

July 19, 2026

Last Modified

July 20, 2026

Advisory Details (4)

Auto-updated Jul 20, 2026
No patch confirmed yet.
generic

ksmbd: validate SID in parent security descriptor during ACL inheritance - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/f0e5c9c663badc9982e6941322eef1cb17de0f11
generic

ksmbd: validate SID in parent security descriptor during ACL inheritance - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/69f030cf95488ae1186c72ac8c66fd279664ea7f
generic

ksmbd: validate SID in parent security descriptor during ACL inheritance - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/1c9d0646a9959752f11ca1080dc1ff26bd1756cb
generic

ksmbd: validate SID in parent security descriptor during ACL inheritance - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/18d8db24b0a5b7be4829238dd4022236df02d421

Vendor Advisories for CVE-2026-64138(2)

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

Patch Availability(2)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-tools-oracle-7.0 (7.0.0-1008.8) @ resolute2026-07-26ubuntu
ubuntulinux-tools-azure-fde-7.0 (7.0.0-1009.9) @ resolute2026-07-26ubuntu

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.

All Vendor Advisories

(2)

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 25× in last 7d / 30× 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.

  1. 2026-07-27 08:31 UTCGHSA enrichment
  2. 2026-07-26 21:41 UTCEG score recompute
  3. 2026-07-26 21:41 UTCGHSA enrichment
  4. 2026-07-26 14:54 UTCEPSS rescore
  5. 2026-07-26 14:54 UTCEPSS rescore
  6. 2026-07-26 10:52 UTCEG score recompute
  7. 2026-07-26 10:52 UTCVendor advisory
  8. 2026-07-26 10:52 UTCGHSA enrichment
  9. 2026-07-25 14:18 UTCEPSS rescore
  10. 2026-07-25 14:18 UTCEPSS rescore
  11. 2026-07-24 14:18 UTCEPSS rescore
  12. 2026-07-24 14:18 UTCEPSS rescore
  13. 2026-07-23 14:18 UTCEPSS rescore
  14. 2026-07-23 14:18 UTCEPSS rescore
  15. 2026-07-23 03:22 UTCEG score recompute
  16. 2026-07-22 14:08 UTCEPSS rescore
  17. 2026-07-22 14:08 UTCEPSS rescore
  18. 2026-07-21 15:25 UTCEPSS rescore
  19. 2026-07-21 15:25 UTCEPSS rescore
  20. 2026-07-20 17:18 UTCEG score recompute
  21. 2026-07-20 17:18 UTCGHSA enrichment
  22. 2026-07-20 17:08 UTCEPSS rescore
  23. 2026-07-20 14:33 UTCEG score recompute▲ 8.80
  24. 2026-07-20 14:33 UTCGHSA enrichment
  25. 2026-07-20 14:32 UTCMITRE cvelistV5CVSS v3 → 8.8 · severity → HIGH
Show 5 more
  1. 2026-07-20 08:34 UTCNVD update
  2. 2026-07-20 07:07 UTCMITRE cvelistV5
  3. 2026-07-19 17:49 UTCNVD update
  4. 2026-07-19 16:08 UTCEG score recompute
  5. 2026-07-19 16:03 UTCMITRE cvelistV5first tracked

Related CVEs(same vendor)

Frequently asked(5)

What is CVE-2026-64138?
CVE-2026-64138 is a high vulnerability published on July 19, 2026. In the Linux kernel, the following vulnerability has been resolved: ksmbd: validate SID in parent security descriptor during ACL inheritance Introduce smbvalidatentsd_sid() helper to safely validate Owner SID and Group SID inside the NT Security Descriptor (smb_ntsd) retrieved from the parent…
When was CVE-2026-64138 disclosed?
CVE-2026-64138 was first published in the National Vulnerability Database on July 19, 2026, with the most recent update on July 20, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-64138 actively exploited?
CVE-2026-64138 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 66.0% of all scored CVEs.
What is the CVSS score of CVE-2026-64138?
CVE-2026-64138 has a CVSS v3 base score of 8.8 (NVD).
How do I remediate CVE-2026-64138?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-64138, 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

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