CVE-2026-31476

Description

In the Linux kernel, the following vulnerability has been resolved: ksmbd: do not expire session on binding failure When a multichannel session binding request fails (e.g. wrong password), the error path unconditionally sets sess->state = SMB2_SESSION_EXPIRED. However, during binding, sess points to the target session looked up via ksmbd_session_lookup_slowpath() -- which belongs to another connection's user. This allows a remote attacker to invalidate any active session by simply sending a binding request with a wrong password (DoS). Fix this by skipping session expiration when the failed request was a binding attempt, since the session does not belong to the current connection. The reference taken by ksmbd_session_lookup_slowpath() is still correctly released via ksmbd_user_session_put().

References

• https://git.kernel.org/stable/c/1d1888b4a7aec518b707f6eca0bf08992c0e8da3
• https://git.kernel.org/stable/c/6fafc4c4238e538969f1375f9ecdc6587c53f1cc
• https://git.kernel.org/stable/c/9bbb19d21ded7d78645506f20d8c44895e3d0fb9
• https://git.kernel.org/stable/c/a897064a457056acb976e20e3007cdf553de340f
• https://git.kernel.org/stable/c/e0e5edc81b241c70355217de7e120c97c3429deb