The vulnerability in the Linux kernel’s ksmbd component causes the DACL permission checks to ignore Authenticated Users ACE entries and to aggregate all ACE access masks without filtering for the correct subject. As a result, a file that should be accessible to an authenticated user may be denied, and conversely, permissions belonging to an unrelated principal can be incorrectly granted. This mis‑authorization can lead to either denial of legitimate access or unauthorized escalation of file privileges. The flaw manifests as status codes such as STATUS_ACCESS_DENIED or STATUS_PRIVILEGE_NOT_HELD, undermining the expected security boundaries enforced by SMB clients. The weakness pertains to improper authorization logic, directly impacting confidentiality, integrity, and availability of protected files.

All Linux kernel installations that provide the ksmbd SMB server component are affected. The advisory does not specify particular kernel releases, which suggests that any version containing the unpatched ksmbd access‑check logic could be vulnerable. Administrators should determine whether their current kernel includes the ksmbd components described and plan for an update if the kernel is older or otherwise unpatched.

With a CVSS score of 8.1, the vulnerability is considered high severity. The EPSS score is < 1%, indicating a very low but non‑zero exploitation probability. The nature of the flaw—triggered via SMB file access requests on a remote host—implies that a network attacker could exploit it by authenticating to a ksmbd service and manipulating ACL entries or crafted file access requests. The vulnerability is not listed in the CISA KEV catalog, indicating that no publicly known exploits have been confirmed at this time. However, the remote exploitation potential and the high CVSS score warrant preemptive remediation.