CVE-2026-90153: In the Linux kernel, the following vulnerability has been resolved: ksmbd: bound smb_check_perm_dacl() ACE walks by DAC

A vulnerability in the Linux kernel's ksmbd (SMB server) allowed incorrect permission checks because the code was reading access control entries (ACEs, which are rules that grant or deny permissions) beyond the declared size of a DACL (discretionary access control list, a data structure that stores permission rules). This meant an attacker could craft a malicious permission list with an ACE placed outside its declared boundaries, and the server would incorrectly accept it during file access validation, potentially granting unauthorized access.