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ksmbd: track the connection owning a byte-range lock

Type: advisorySources: OSV

In the Linux kernel, the following vulnerability has been resolved: ksmbd: track the connection owning a byte-range lock SMB2_LOCK adds each granted byte-range lock to both the file lock list and the lock list of the connection which handled the request. The final close and durable handle paths, however, remove the connection list entry while holding fp->conn->llist_lock. With SMB3 multichannel, the connection handling the LOCK request can be different from the connection which opened the file. The entry can therefore be removed under a different spinlock from the one protecting the list it belongs to. A concurrent traversal can then access freed struct ksmbd_lock and struct file_lock objects. Record the connection owning each lock's clist entry and hold a reference to it while the entry is linked. Use that connection and its llist_lock for unlock, rollback, close, and durable preserve. Durable reconnect assigns the new connection as the owner when publishing the locks again.

Products
Kernel
Affected versions
Not specified
Fixed versions
5.15.212, 6.1.178, 6.12.97, 6.18.40, 6.6.145, 7.1.4
CVEs
CVE-2026-64390
Confirmed fixed CVEs
Not specified
Updated in this feed
4 Nov 2026, 13:28 UTC · Revision 1

Source evidence

ksmbd: track the connection owning a byte-range lock

core-osv · Original source

Published 25 Jul 2026, 08:50 UTC

In the Linux kernel, the following vulnerability has been resolved: ksmbd: track the connection owning a byte-range lock SMB2_LOCK adds each granted byte-range lock to both the file lock list and the lock list of the connection which handled the request. The final close and durable handle paths, however, remove the connection list entry while holding fp->conn->llist_lock. With SMB3 multichannel, the connection handling the LOCK request can be different from the connection which opened the file. The entry can therefore be removed under a different spinlock from the one protecting the list it belongs to. A concurrent traversal can then access freed struct ksmbd_lock and struct file_lock objects. Record the connection owning each lock's clist entry and hold a reference to it while the entry is linked. Use that connection and its llist_lock for unlock, rollback, close, and durable preserve. Durable reconnect assigns the new connection as the owner when publishing the locks again.

osv:CVE-2026-64390

Kernel

Fixed versions: 5.15.212, 6.1.178, 6.6.145, 6.12.97, 6.18.40, 7.1.4

Complete source record
{
  "id": "83a1031d8a76dfff6a67e19db1a83f0444c9976bef70bef8472ffdf4baf715c9",
  "url": "https://osv.dev/vulnerability/CVE-2026-64390",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ksmbd: track the connection owning a byte-range lock",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: ksmbd: track the connection owning a byte-range lock SMB2_LOCK adds each granted byte-range lock to both the file lock list and the lock list of the connection which handled the request. The final close and durable handle paths, however, remove the connection list entry while holding fp->conn->llist_lock. With SMB3 multichannel, the connection handling the LOCK request can be different from the connection which opened the file. The entry can therefore be removed under a different spinlock from the one protecting the list it belongs to. A concurrent traversal can then access freed struct ksmbd_lock and struct file_lock objects. Record the connection owning each lock's clist entry and hold a reference to it while the entry is linked. Use that connection and its llist_lock for unlock, rollback, close, and durable preserve. Durable reconnect assigns the new connection as the owner when publishing the locks again.",
    "evidence": "osv:CVE-2026-64390",
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      ],
      "modified": "2026-10-28T02:30:35.795126011Z",
      "provider": "osv",
      "references": [
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      "provider_metadata": {
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    },
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  "source_id": "core-osv",
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  "published_at": "2026-07-25T08:50:37.406+00:00"
}