{"id":"CVE-2026-53198","summary":"ksmbd: fix use-after-free of a deferred file_lock on double SMB2_CANCEL","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix use-after-free of a deferred file_lock on double SMB2_CANCEL\n\nA deferred byte-range lock (an SMB2_LOCK that blocks) registers an async work on\nconn-\u003easync_requests via setup_async_work(), with cancel_fn =\nsmb2_remove_blocked_lock and cancel_argv[0] pointing at the struct file_lock.\n\nWhen the request is cancelled, the worker frees the file_lock with\nlocks_free_lock() and takes the cancelled early-exit, which \"goto out\"s and never\nreaches release_async_work() -- the only site that unlinks the work from\nconn-\u003easync_requests and clears cancel_fn/cancel_argv. The work therefore stays\nmatchable on async_requests with a live cancel_fn pointing at the freed file_lock,\nuntil connection teardown finally runs release_async_work().\n\nsmb2_cancel() fires cancel_fn unconditionally with no state guard, so a second\nSMB2_CANCEL for the same AsyncId, arriving in that window, re-runs\nsmb2_remove_blocked_lock() on the freed file_lock -- a slab use-after-free:\n\n  BUG: KASAN: slab-use-after-free in __locks_delete_block\n    __locks_delete_block\n    locks_delete_block\n    ksmbd_vfs_posix_lock_unblock\n    smb2_remove_blocked_lock\n    smb2_cancel                 \u003c- 2nd SMB2_CANCEL fires cancel_fn\n    handle_ksmbd_work\n  Allocated by ...: locks_alloc_lock \u003c- smb2_lock\n  Freed by ...:     locks_free_lock  \u003c- smb2_lock (cancelled branch)\n  ... cache file_lock_cache of size 192\n\nReproduced on mainline with KASAN by an authenticated SMB client.\n\nSkip a work whose state is already KSMBD_WORK_CANCELLED so its cancel callback\ncannot be fired a second time.","modified":"2026-07-08T08:07:24.480492652Z","published":"2026-06-25T08:39:07.650Z","related":["CGA-p98j-2g7f-hqx8"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53198.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/0da2e073f9cbf4985a0fd9acb71bc5ff599f8afd"},{"type":"WEB","url":"https://git.kernel.org/stable/c/14d2eee0193ac3cd1bf3d014373449f0b8d35d6d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/2b2eda2821cff1d1b5a423b6ee7d8fc6fbc8e694"},{"type":"WEB","url":"https://git.kernel.org/stable/c/89ae9df09d2c1fb4a4eb495c113a7ce1dca34147"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b7063c7426ea5a4d15e01b60538718765392f49d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f580d27e8928828693df44ba2db0fffdbe11dfea"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53198.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53198"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9"},{"fixed":"b7063c7426ea5a4d15e01b60538718765392f49d"},{"fixed":"0da2e073f9cbf4985a0fd9acb71bc5ff599f8afd"},{"fixed":"89ae9df09d2c1fb4a4eb495c113a7ce1dca34147"},{"fixed":"14d2eee0193ac3cd1bf3d014373449f0b8d35d6d"},{"fixed":"2b2eda2821cff1d1b5a423b6ee7d8fc6fbc8e694"},{"fixed":"f580d27e8928828693df44ba2db0fffdbe11dfea"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53198.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.15.0"},{"fixed":"6.1.176"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.143"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.94"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.36"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.0.13"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53198.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}