CVE-2026-80926

CVE CVE-2026-80926EUVD EUVD-2026-76248Published 2026-09-11T19:37:29.000ZLast changed 2026-09-13T06:28:07.000ZCVSS 9.8

What the advisory describes

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free in oplock break notification smb2_oplock_break_noti() reads opinfo->conn without any lock and dereferences it after two allocations which may sleep. When the durable handle owning the oplock is disconnected, session_fd_check() clears opinfo->conn and drops its conn reference under ci->m_lock, and the last ksmbd_conn_put() frees the connection. A break triggered by another connection that races with the teardown can then resurrect the freed connection: ksmbd_conn_get() is a plain atomic_inc, and the queued break work later dereferences the stale conn via ksmbd_conn_write(), a use-after-free reachable by any authenticated client holding a durable batch oplock. Thread the caller's inode into the notification path instead of taking a new reference on it. Every caller of oplock_break() already holds a live ksmbd_file (or an explicit ksmbd_inode_lookup_lock() reference, in the parent lease break paths) on the inode that owns the break target's oplock list, so ci cannot be freed during the call, and its lock can be taken without dereferencing opinfo->o_fp, which a concurrent close may free. Select and pin the connection under ci->m_lock, the same lock session_fd_check() and ksmbd_reopen_durable_fd() use to update opinfo->conn, so a concurrent detach either loses the race to the clear or keeps the connection alive until the notification work releases it. Transfer the reference to the work item and release it on allocation failures.

Source: EUVD (ENISA), in the words of the advisory.

Products the advisory names

These come from the advisory itself, not from any check we performed.

• Linux — Linux patch: 7.2.5; 7.0.13 <7.1; 7.1; 6.6.143 <6.7; patch: 7.3-rc2; 945a86b21b40fb17183f5b27461baa6f03e2467f; b003086d76968298f22e7cf62239833b5a3a06b1 <8cc98db4fc590e6c7d9db6529320982ee16c5d1d; 1ff58dcfcab434ebb51649da33774fbb8e1f7b67; patch: 6.18.51; 6.18.36 <6.18.51; e735dbd489e3ea02be78dba991056fe1138be51e <c8279ae8df68cce9cd3b785e85f7a86c80a46e78; 6.12.94 <6.13; 75e33deda658c1ab3a9336cbdb1436536f9b3660; b003086d76968298f22e7cf62239833b5a3a06b1 <0e753899627b5e28a9fea8bca98262a6f65a2452; patch: 0

The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.

Carried in the product catalogue

An estate covering these products can be recorded in Patchlage. An advisory about them appears in the next morning's situation report.

• Linux — Linux

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