{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-80926","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-08-26T14:34:25.802Z","datePublished":"2026-09-11T19:37:29.855Z","dateUpdated":"2026-10-03T10:56:18.066Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-10-03T10:56:18.066Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix use-after-free in oplock break notification\n\nsmb2_oplock_break_noti() reads opinfo->conn without any lock and\ndereferences it after two allocations which may sleep.  When the\ndurable handle owning the oplock is disconnected, session_fd_check()\nclears opinfo->conn and drops its conn reference under ci->m_lock, and\nthe last ksmbd_conn_put() frees the connection.  A break triggered by\nanother connection that races with the teardown can then resurrect the\nfreed connection: ksmbd_conn_get() is a plain atomic_inc, and the\nqueued break work later dereferences the stale conn via\nksmbd_conn_write(), a use-after-free reachable by any authenticated\nclient holding a durable batch oplock.\n\nThread the caller's inode into the notification path instead of taking\na new reference on it.  Every caller of oplock_break() already holds a\nlive ksmbd_file (or an explicit ksmbd_inode_lookup_lock() reference,\nin the parent lease break paths) on the inode that owns the break\ntarget's oplock list, so ci cannot be freed during the call, and its\nlock can be taken without dereferencing opinfo->o_fp, which a\nconcurrent close may free.  Select and pin the connection under\nci->m_lock, the same lock session_fd_check() and\nksmbd_reopen_durable_fd() use to update opinfo->conn, so a concurrent\ndetach either loses the race to the clear or keeps the connection\nalive until the notification work releases it.  Transfer the reference\nto the work item and release it on allocation failures."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":9.8,"baseSeverity":"CRITICAL"},"scenarios":[{"lang":"en","value":"AV:N - ksmbd is the in-kernel SMB server on TCP/445; smb2_oplock_break_noti() is reached from remote SMB2 CREATE/WRITE/truncate that breaks a durable batch oplock, and the racing teardown is a remote disconnect or SMB2 LOGOFF, so a network peer fully drives the UAF.\nAC:L - The attacker controls both sides of the race: one connection holds a durable batch oplock while a second opens the same file to force oplock_break(), and dropping the first connection runs session_fd_check() during the sleeping allocations before ksmbd_conn_get(); the window is retryable.\nPR:N - ksmbd shares are commonly exposed with guest/anonymous mapping, so a remote client can SESSION_SETUP, TREE_CONNECT, CREATE a durable batch oplock, and trigger the racing disconnect without a privileged host account; no meaningful credential gate protects this path.\nUI:N - No victim action is required; the attacker opens both SMB connections, requests the durable batch oplock, forces the conflicting open, and drops the first connection entirely on their own.\nS:U - The freed ksmbd_conn and resulting kernel heap corruption stay within the ksmbd/kernel security authority on the SMB server host; this is not a VM, IOMMU, or sandbox escape.\nC:H - Use-after-free of struct ksmbd_conn lets the attacker reclaim the slab object; __smb2_oplock_break_noti() then reads conn->transport and related fields from attacker-controlled memory, enabling kernel pointer and data disclosure.\nI:H - ksmbd_conn_write() calls conn->transport->ops->writev and ksmbd_conn_lock() on the freed object, so heap spraying the reclaimed ksmbd_conn yields an arbitrary function-pointer call and mutex writes into attacker-chosen memory.\nA:H - Even without a fully controlled exploit, using a freed ksmbd_conn (mutex lock, transport dereference, r_count/waitqueue) causes kernel memory corruption, oops, or panic and takes down the host."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/oplock.c"],"versions":[{"version":"945a86b21b40fb17183f5b27461baa6f03e2467f","lessThan":"892f643b141aee3f7aa7c0fc61ddcb55c59f1996","status":"affected","versionType":"git"},{"version":"1ff58dcfcab434ebb51649da33774fbb8e1f7b67","lessThan":"5de0527f782430b1109a447646e32033ad018a6a","status":"affected","versionType":"git"},{"version":"e735dbd489e3ea02be78dba991056fe1138be51e","lessThan":"c8279ae8df68cce9cd3b785e85f7a86c80a46e78","status":"affected","versionType":"git"},{"version":"b003086d76968298f22e7cf62239833b5a3a06b1","lessThan":"8cc98db4fc590e6c7d9db6529320982ee16c5d1d","status":"affected","versionType":"git"},{"version":"b003086d76968298f22e7cf62239833b5a3a06b1","lessThan":"0e753899627b5e28a9fea8bca98262a6f65a2452","status":"affected","versionType":"git"},{"version":"75e33deda658c1ab3a9336cbdb1436536f9b3660","status":"affected","versionType":"git"},{"version":"6.6.143","lessThan":"6.6.158","status":"affected","versionType":"semver"},{"version":"6.12.94","lessThan":"6.12.111","status":"affected","versionType":"semver"},{"version":"6.18.36","lessThan":"6.18.51","status":"affected","versionType":"semver"},{"version":"7.0.13","lessThan":"7.1","status":"affected","versionType":"semver"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/oplock.c"],"versions":[{"version":"7.1","status":"affected"},{"version":"0","lessThan":"7.1","status":"unaffected","versionType":"semver"},{"version":"6.6.158","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.111","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.51","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.5","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3-rc2","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6.143","versionEndExcluding":"6.6.158"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12.94","versionEndExcluding":"6.12.111"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.18.36","versionEndExcluding":"6.18.51"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.1","versionEndExcluding":"7.2.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.1","versionEndExcluding":"7.3-rc2"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.0.13"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/892f643b141aee3f7aa7c0fc61ddcb55c59f1996"},{"url":"https://git.kernel.org/stable/c/5de0527f782430b1109a447646e32033ad018a6a"},{"url":"https://git.kernel.org/stable/c/c8279ae8df68cce9cd3b785e85f7a86c80a46e78"},{"url":"https://git.kernel.org/stable/c/8cc98db4fc590e6c7d9db6529320982ee16c5d1d"},{"url":"https://git.kernel.org/stable/c/0e753899627b5e28a9fea8bca98262a6f65a2452"}],"title":"ksmbd: fix use-after-free in oplock break notification","x_generator":{"engine":"bippy-1.2.0"}}}}