The ksmbd component of the Linux kernel does not validate the Owner and Group Security Identifiers contained in the NT Security Descriptor of a parent directory during ACL inheritance. This omission allows an attacker to craft or alter an ACL for a shared directory so that the resulting permissions grant them privileges beyond the intended scope. The flaw is specific to the SMB protocol handling, leading to possible unauthorized access or privilege escalation on the host.

Linux kernel builds that lack the smb_validate_ntsd_sid() patch are at risk. The CNA identifies the affected vendor as Linux and the product as the Linux kernel; no specific kernel versions are listed, so any kernel version prior to the inclusion of the helper function should be considered vulnerable.

The CVSS score of 8.8 signals high severity. The EPSS score of less than 1% indicates a low probability of widespread exploitation at present, and the vulnerability is not listed in the CISA KEV catalog. The likely attack vector is remote interaction with the SMB service, inferred from the nature of the defect; an attacker who can influence the creation or modification of ACLs on a shared directory could exploit the missing SID validation to gain unauthorized access or elevate privileges.