CVE-2026-98870
Full vulnerability record from the local CVENow database.
Description
In 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.
View original CVE JSON
{
"id": "CVE-2026-98870",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-10-23T12:18:20.397",
"lastModified": "2026-10-24T14:16:47.773",
"vulnStatus": "Received",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "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 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."
}
],
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "unaffected",
"programFiles": [
"fs/smb/server/mgmt/user_session.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "b1b6ed903a6e2b3505a48706bcd499b447ef9e44",
"lessThan": "f8200bb4994e65a2e5c5b314789eeae39078619d",
"versionType": "git",
"status": "affected"
},
{
"version": "47b018dba6ec7ebf403fd2d1e713bc7acc9bbb23",
"lessThan": "9cd6d714d3ca0cff296542dc989696884e41970f",
"versionType": "git",
"status": "affected"
},
{
"version": "9ef4dfd5edbd02f4bf10cd420a30896093d98a67",
"lessThan": "b145f9b56c87f9c23ad5464ab0844dbc1de12b36",
"versionType": "git",
"status": "affected"
},
{
"version": "5a5b0b7a01fe19b383b3c046546b5ae30c1a7d71",
"lessThan": "a15cae16f4432a5ad919ee633e31b07178492955",
"versionType": "git",
"status": "affected"
},
{
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"lessThan": "b10665730fbf6b5e45fe422badcbbc3f0df96ef5",
"versionType": "git",
"status": "affected"
},
{
"version": "e632f21a8bc0c59abc4960482836ac3782db93c0",
"versionType": "git",
"status": "affected"
},
{
"version": "5.15.222",
"lessThan": "5.16",
"versionType": "semver",
"status": "affected"
}
]
},
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "unaffected",
"programFiles": [
"fs/smb/server/mgmt/user_session.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
}
]
}
],
"metrics": {
"cvssMetricV31": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary",
"cvssData": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"baseScore": 8.8,
"baseSeverity": "HIGH",
"attackVector": "NETWORK",
"attackComplexity": "LOW",
"privilegesRequired": "LOW",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"availabilityImpact": "HIGH"
},
"exploitabilityScore": 2.8,
"impactScore": 5.9
}
]
},
"references": [
{
"url": "https://git.kernel.org/stable/c/9cd6d714d3ca0cff296542dc989696884e41970f",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/a15cae16f4432a5ad919ee633e31b07178492955",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/b10665730fbf6b5e45fe422badcbbc3f0df96ef5",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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{
"url": "https://git.kernel.org/stable/c/b145f9b56c87f9c23ad5464ab0844dbc1de12b36",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/f8200bb4994e65a2e5c5b314789eeae39078619d",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
]
}