Linux Kernel Vulnerability in SMB Server Affects Security Descriptor Validation

CVE-2026-64138

What is CVE-2026-64138?

A vulnerability in the Linux kernel's SMB server component, ksmbd, allows for unsafe validation of Security Identifiers (SIDs) in the parent security descriptors during Access Control List (ACL) inheritance. The introduced smb_validate_ntsd_sid() function enhances the validation process for Owner SID and Group SID within the NT Security Descriptor retrieved from parent directories, ensuring that only properly validated SIDs are referenced. This measure mitigates potential access control weaknesses introduced by flawed SID management, contributing to overall system integrity.

References