CVSS 7.5 · High EPSS 0,66%
Kerentanan NULL Pointer Dereference pada linux kernel. Skor CVSS 3.1 7.5 (High) menurut CNA.
In the Linux kernel, the following vulnerability has been resolved: ksmbd: reject non-VALID session in compound request branch smb2_check_user_session() takes a shortcut for any operation that is not the first in a COMPOUND request: it reuses work->sess (the session bound by the first operation) and validates only the SessionId, then returns "valid". It never re-checks work->sess->state == SMB2_SESSION_VALID, and a SessionId of 0xFFFFFFFFFFFFFFFF (ULLONG_MAX, the MS-SMB2 related-operation value) skips even the id comparison. The standalone path (ksmbd_session_lookup_all() plus the SESSION_SETUP state machine) does enforce the VALID state; the compound branch bypasses all of it. A SESSION_SETUP carrying only an NTLM Type-1 (NtLmNegotiate) blob publishes a fresh SMB2_SESSION_IN_PROGRESS session whose sess->user is still NULL (->user is assigned later, by ntlm_authenticate()). Used as operation 1 of a COMPOUND with operation 2 = TREE_CONNECT (related, SessionId=ULLONG_MAX, \\host\IPC$), the tree-connect then runs on that IN_PROGRESS session and reaches ksmbd_ipc_tree_connect_request(), which dereferences user_name(sess->user) with sess->user == NULL (transport_ipc.c:687/701/704) -> remote NULL-pointer dereference and a kernel Oops that wedges the ksmbd worker for all clients. Reject any non-first compound operation that lands on a session which is not SMB2_SESSION_VALID, mirroring the validity the standalone lookup path enforces. SESSION_SETUP itself legitimately runs on an IN_PROGRESS session, but it is never carried as a non-first compound operation, so multi-leg authentication is unaffected by this check.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
· uraikan di kalkulator | Vendor | Produk | Versi terdampak |
|---|---|---|
| linux | linux kernel | Versi 5.15.121 hingga sebelum 5.15.211 |
| linux | linux kernel | Versi 6.1.36 hingga sebelum 6.1.177 |
| linux | linux kernel | Versi 6.3.10 hingga sebelum 6.4 |
| linux | linux kernel | Versi 6.4.1 hingga sebelum 6.6.144 |
| linux | linux kernel | Versi 6.7 hingga sebelum 6.12.95 |
| linux | linux kernel | Versi 6.13 hingga sebelum 6.18.37 |
| linux | linux kernel | Versi 6.19 hingga sebelum 7.0.14 |
| linux | linux kernel | Versi 7.1 hingga sebelum 7.1.2 |
| linux | linux kernel | Versi 6.4 |