CVE-2026-68130

Description

In the Linux kernel, the following vulnerability has been resolved: ksmbd: defer destroy_previous_session() until after NTLM authentication In ntlm_authenticate(), destroy_previous_session() is called using a user pointer resolved from the client-supplied NTLM blob username field before the NTLMv2 response is validated. An authenticated attacker can set the NTLM blob username to match a victim account and set PreviousSessionId to the victim's session ID; destroy_previous_session() destroys the victim's session while ksmbd_decode_ntlmssp_auth_blob() subsequently rejects the request with -EPERM. Move destroy_previous_session() and the prev_id assignment to after ksmbd_decode_ntlmssp_auth_blob() returns success and use sess->user rather than the pre-authentication lookup result. This matches the ordering already used by krb5_authenticate(), where destroy_previous_session() is called only after ksmbd_krb5_authenticate() returns success.

References

• https://git.kernel.org/stable/c/0ff12308c8a6c16ab68f0a487ffa93d69001dc18
• https://git.kernel.org/stable/c/18705cace0619fd2123737dcd028147774f38181
• https://git.kernel.org/stable/c/243f1614ef2aca2d62a744575f1c24b07cd42757
• https://git.kernel.org/stable/c/5c833074b549e5db125436a6f681af682261f785
• https://git.kernel.org/stable/c/c74801ee524f477c174a1899782b6c3b6918d407