CVE-2026-43350

A flaw was found in the Linux kernel CIFS/SMB client when parsing DACLs (parse_dacl). An ACE could match the Unix NFS mode SID prefix with only two subauthorities; code then read sub_auth[2] for mode bits, accessing four bytes past the end of the ACE buffer. Upstream requires num_subauth >= 3 before treating an ACE as an NFS mode SID.

Red Hat acknowledges the upstream Linux kernel correction for «smb» as described in COMMENT_ZERO. Fixes are delivered through standard kernel errata for supported products. Operational exposure depends on whether this subsystem or driver is active in your configuration.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

To mitigate this issue, prevent the cifs module from being loaded. See https://access.redhat.com/solutions/41278 for instructions.