Linux Kernel ksmbd Session Binding Flaw Global Session Access
CVE-2026-52911 Published on June 21, 2026
ksmbd: scope conn->binding slowpath to bound sessions only
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: scope conn->binding slowpath to bound sessions only
When the binding SESSION_SETUP sets conn->binding = true, the flag stays
set after the call so that the global session lookup in
ksmbd_session_lookup_all() can find the session, which was not added to
conn->sessions. Because the flag is connection-wide, the global lookup
path will also resolve any other session by id if asked.
Tighten the global lookup so that the returned session must have this
connection registered in its channel xarray (sess->ksmbd_chann_list).
The channel entry is installed by the existing binding_session path in
ntlm_authenticate()/krb5_authenticate() when a SESSION_SETUP completes
successfully, so this condition is a strict equivalent of "this
connection has been accepted as a channel of this session". Connections
that have not bound to a given session cannot reach it via the global
table.
The existing conn->binding gate for entering the slowpath is preserved
so that non-binding connections keep the fast-path-only behavior, and
the session->state check is unchanged.
Products Associated with CVE-2026-52911
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Affected Versions
Linux:- Version f5a544e3bab78142207e0242d22442db85ba1eff and below e74c00c6af428a39e564cdc5bd3a3648c6d8de87 is affected.
- Version f5a544e3bab78142207e0242d22442db85ba1eff and below e3a93ce6e25757b8f375e38b8f91e1d9da4edc1a is affected.
- Version f5a544e3bab78142207e0242d22442db85ba1eff and below 1ff46c9915c1cbf454db58a8cb87f7cac818e6a6 is affected.
- Version f5a544e3bab78142207e0242d22442db85ba1eff and below 974c1c224e85549dc3459f3bb2255bbbdd2b9372 is affected.
- Version f5a544e3bab78142207e0242d22442db85ba1eff and below 2cc8a4db633b10715450b291c1343859a4b2c509 is affected.
- Version f5a544e3bab78142207e0242d22442db85ba1eff and below 1e2bec062c5c9ec282636715166056d0998d746d is affected.
- Version f5a544e3bab78142207e0242d22442db85ba1eff and below b0da97c034b6107d14e537e212d4ce8b22109a58 is affected.
- Version 5.15 is affected.
- Before 5.15 is unaffected.
- Version 5.15.209, <= 5.15.* is unaffected.
- Version 6.1.175, <= 6.1.* is unaffected.
- Version 6.6.141, <= 6.6.* is unaffected.
- Version 6.12.91, <= 6.12.* is unaffected.
- Version 6.18.33, <= 6.18.* is unaffected.
- Version 7.0.10, <= 7.0.* is unaffected.
- Version 7.1, <= * is unaffected.