High severity · published Jul 25, 2026
CVE-2026-64390
ksmbd: track the connection owning a byte-range lock
8.8
CVSS
0.5%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 40% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
KE
Kernel · Linux
5.15 before 5.15.212; 5.16 before 6.1.178; 6.2 before 6.6.145; 6.7 before 6.12.97; 6.13 before 6.18.40; 6.19 before 7.1.4 · source: NVD
LI
Linux · Linux
f5a544e3bab78142207e0242d22442db85ba1eff before 22d38cf75b556c20b039743bdf3654d535b858be; f5a544e3bab78142207e0242d22442db85ba1eff before 66eb3643164e5e1029907793926c132f8b5c6148; f5a544e3bab78142207e0242d22442db85ba1eff before ea5c9bf99f626a15cc59f645dc895f2b3f01992e; f5a544e3bab78142207e0242d22442db85ba1eff before fe20d492a69a6f79e637f438072b212e21ed3b78; f5a544e3bab78142207e0242d22442db85ba1eff before 427faaa52b0b399940c1a88065a5c310d10dad15; f5a544e3bab78142207e0242d22442db85ba1eff before 5fecc15a30cb9ebd310f7b52c1ab607edcea78f6; +2 more · source: vendor