CVE-2026-64138

ksmbd: validate SID in parent security descriptor during ACL inheritance

CVE-2026-64138 is fixed in linux on 1 platform, first by DEBIAN-CVE-2026-64138, released July 20, 2026. It is not reported as exploited. Patch Radar priority: Urgent.

Urgent

CVSS

9.8

Critical

Exploitation

None reported

No vendor assessment

CISA KEV

Not listed

Not in the Known Exploited Vulnerabilities catalog

EPSS

0.0045

39th percentile

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.

Where it's fixed

Product	Fixed in	Fix	Released
Linux
linux · Debian 13.5 (trixie)	6.12.94-1	DEBIAN-CVE-2026-64138	Jul 20, 2026
linux · Debian 14	7.0.12-1	DEBIAN-CVE-2026-64138	Jul 20, 2026

Details

Published
July 19, 2026
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Vendor advisory
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-64138

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