CVE-2026-53383

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description A remote NULL-pointer dereference exists in the ksmbd component of the Linux kernel. The smb2 check user session() function fails to re-verify that a session state is SMB2 SESSION VALID for operations that are not the first in a COMPOUND request. Specifically, when a SESSION SETUP operation with an NTLM Type-1 blob creates a session in the SMB2 SESSION IN PROGRESS state, the sess->user variable remains NULL. If a subsequent TREE CONNECT operation is included in the same COMPOUND request, it can trigger the ksmbd ipc tree connect request() function, which dereferences the NULL sess->user variable. This leads to a kernel Oops, causing the ksmbd worker to hang for all clients.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.