ksmbd: remove stale channels from all sessions on teardown

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-98870
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-23 12:18:20 UTC
Updated2026-10-24 14:16:47 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: ksmbd: remove stale channels from all sessions on teardown ksmbd_sessions_deregister() removes a connection's channels from other sessions' channel lists only while conn->binding is still set: if (conn->binding) { hash_for_each_safe(sessions_table, ...) ksmbd_chann_del(conn, sess); } conn->binding is a transient flag: it is cleared once a binding SESSION_SETUP completes, and also by a subsequent non-binding SESSION_SETUP on the same connection (a reauthentication on a bound channel, or a new SessionId==0 setup). A connection that has bound a channel into another session's ksmbd_chann_list and then clears conn->binding leaves that channel behind when it disconnects: the channel, whose chann->conn points at the now freed struct ksmbd_conn, stays on the owner session's list. When the owning connection later tears down, the second loop dereferences the stale channel: xa_for_each(&sess->ksmbd_chann_list, chann_id, chann) if (chann->conn != conn) ksmbd_conn_set_exiting(chann->conn); /* freed */ which is a use-after-free write into the freed ksmbd_conn (the same stale channel is also walked by show_proc_session() through /proc). The session is leaked as well, because its channel list never empties. Remove the conn->binding gate so a connection always removes its channels from every session on teardown.

Risk And Classification

Primary CVSS: v3.1 8.8 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary8.8HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED8.8HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected b1b6ed903a6e2b3505a48706bcd499b447ef9e44 f8200bb4994e65a2e5c5b314789eeae39078619d git Not specified
CNA Linux Linux affected 47b018dba6ec7ebf403fd2d1e713bc7acc9bbb23 9cd6d714d3ca0cff296542dc989696884e41970f git Not specified
CNA Linux Linux affected 9ef4dfd5edbd02f4bf10cd420a30896093d98a67 b145f9b56c87f9c23ad5464ab0844dbc1de12b36 git Not specified
CNA Linux Linux affected 5a5b0b7a01fe19b383b3c046546b5ae30c1a7d71 a15cae16f4432a5ad919ee633e31b07178492955 git Not specified
CNA Linux Linux affected faf8578c77f3d846aca9cd882c293e03eafcc6df b10665730fbf6b5e45fe422badcbbc3f0df96ef5 git Not specified
CNA Linux Linux affected e632f21a8bc0c59abc4960482836ac3782db93c0 git Not specified
CNA Linux Linux affected 5.15.222 5.16 semver Not specified
CNA Linux Linux Not specified Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/b10665730fbf6b5e45fe422badcbbc3f0df96ef5 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/a15cae16f4432a5ad919ee633e31b07178492955 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/f8200bb4994e65a2e5c5b314789eeae39078619d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/9cd6d714d3ca0cff296542dc989696884e41970f 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/b145f9b56c87f9c23ad5464ab0844dbc1de12b36 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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