{"id":"CVE-2026-98870","title":"ksmbd: remove stale channels from all sessions on teardown","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: remove stale channels from all sessions on teardown\n\nksmbd_sessions_deregister() removes a connection's channels from other\nsessions' channel lists only while co…","severity":"high","cvss":8.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= b1b6ed903a6e2b3505a48706bcd499b447ef9e44 < f8200bb4994e65a2e5c5b314789eeae39078619d","Linux >= 47b018dba6ec7ebf403fd2d1e713bc7acc9bbb23 < 9cd6d714d3ca0cff296542dc989696884e41970f","Linux >= 9ef4dfd5edbd02f4bf10cd420a30896093d98a67 < b145f9b56c87f9c23ad5464ab0844dbc1de12b36","Linux >= 5a5b0b7a01fe19b383b3c046546b5ae30c1a7d71 < a15cae16f4432a5ad919ee633e31b07178492955","Linux >= faf8578c77f3d846aca9cd882c293e03eafcc6df < b10665730fbf6b5e45fe422badcbbc3f0df96ef5","Linux e632f21a8bc0c59abc4960482836ac3782db93c0","Linux >= 5.15.222 < 5.16","Linux"],"published":"2026-10-23","updated":"2026-10-24","sourceUpdated":"2026-10-24T14:09:26.805Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98870","references":[{"url":"https://git.kernel.org/stable/c/f8200bb4994e65a2e5c5b314789eeae39078619d"},{"url":"https://git.kernel.org/stable/c/9cd6d714d3ca0cff296542dc989696884e41970f"},{"url":"https://git.kernel.org/stable/c/b145f9b56c87f9c23ad5464ab0844dbc1de12b36"},{"url":"https://git.kernel.org/stable/c/a15cae16f4432a5ad919ee633e31b07178492955"},{"url":"https://git.kernel.org/stable/c/b10665730fbf6b5e45fe422badcbbc3f0df96ef5"}],"tags":["cve.org"],"epss":0.0025,"epssPercentile":0.15509,"ingestedAt":"2026-10-23T13:24:55.586Z","slug":"CVE-2026-98870","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: remove stale channels from all sessions on teardown\n\nksmbd_sessions_deregister() removes a connection's channels from other\nsessions' channel lists only while conn->binding is still set:\n\n\tif (conn->binding) {\n\t\thash_for_each_safe(sessions_table, ...)\n\t\t\tksmbd_chann_del(conn, sess);\n\t}\n\nconn->binding is a transient flag: it is cleared once a binding\nSESSION_SETUP completes, and also by a subsequent non-binding\nSESSION_SETUP on the same connection (a reauthentication on a bound\nchannel, or a new SessionId==0 setup). A connection that has bound a\nchannel into another session's ksmbd_chann_list and then clears\nconn->binding leaves that channel behind when it disconnects: the\nchannel, whose chann->conn points at the now freed struct ksmbd_conn,\nstays on the owner session's list.\n\nWhen the owning connection later tears down, the second loop\ndereferences the stale channel:\n\n\txa_for_each(&sess->ksmbd_chann_list, chann_id, chann)\n\t\tif (chann->conn != conn)\n\t\t\tksmbd_conn_set_exiting(chann->conn);   /* freed */\n\nwhich is a use-after-free write into the freed ksmbd_conn (the same\nstale channel is also walked by show_proc_session() through /proc). The\nsession is leaked as well, because its channel list never empties.\n\nRemove the conn->binding gate so a connection always removes its\nchannels from every session on teardown.\n\n## Affected\n\n- `Linux >= b1b6ed903a6e2b3505a48706bcd499b447ef9e44 < f8200bb4994e65a2e5c5b314789eeae39078619d`\n- `Linux >= 47b018dba6ec7ebf403fd2d1e713bc7acc9bbb23 < 9cd6d714d3ca0cff296542dc989696884e41970f`\n- `Linux >= 9ef4dfd5edbd02f4bf10cd420a30896093d98a67 < b145f9b56c87f9c23ad5464ab0844dbc1de12b36`\n- `Linux >= 5a5b0b7a01fe19b383b3c046546b5ae30c1a7d71 < a15cae16f4432a5ad919ee633e31b07178492955`\n- `Linux >= faf8578c77f3d846aca9cd882c293e03eafcc6df < b10665730fbf6b5e45fe422badcbbc3f0df96ef5`\n- `Linux e632f21a8bc0c59abc4960482836ac3782db93c0`\n- `Linux >= 5.15.222 < 5.16`\n- `Linux`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":48,"depthScoreParts":{"impact":48.4,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":228920,"id":"CVE-2026-98870","ts":1792854109775,"field":"cvss","old":null,"new":"8.8"},{"seq":228919,"id":"CVE-2026-98870","ts":1792854109775,"field":"severity","old":"none","new":"high"}]}