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CVE-2026-53198

Vulnérabilité élevée dans Linux (Linux)

CVSS 8.8 · Élevée
EPSS 0.4%
Linux•Linux•Versions : <=6.1.*, <=7.0.*, <=6.12.*, 6.12.94, 0, <b7063c7426ea5a4d15e01b60538718765392f49d, <2b2eda2821cff1d1b5a423b6ee7d8fc6fbc8e694, <14d2eee0193ac3cd1bf3d014373449f0b8d35d6d, 6.1.176, <=6.6.*, 7.0.13, <5.15, 6.18.36, e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9, 7.1, 5.15, <=6.18.*, <0da2e073f9cbf4985a0fd9acb71bc5ff599f8afd, <f580d27e8928828693df44ba2db0fffdbe11dfea, <89ae9df09d2c1fb4a4eb495c113a7ce1dca34147, <=*, 6.6.143

Description

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free of a deferred file_lock on double SMB2_CANCEL A deferred byte-range lock (an SMB2_LOCK that blocks) registers an async work on conn->async_requests via setup_async_work(), with cancel_fn = smb2_remove_blocked_lock and cancel_argv[0] pointing at the struct file_lock. When the request is cancelled, the worker frees the file_lock with locks_free_lock() and takes the cancelled early-exit, which "goto out"s and never reaches release_async_work() -- the only site that unlinks the work from conn->async_requests and clears cancel_fn/cancel_argv. The work therefore stays matchable on async_requests with a live cancel_fn pointing at the freed file_lock, until connection teardown finally runs release_async_work(). smb2_cancel() fires cancel_fn unconditionally with no state guard, so a second SMB2_CANCEL for the same AsyncId, arriving in that window, re-runs smb2_remove_blocked_lock() on the freed file_lock -- a slab use-after-free: BUG: KASAN: slab-use-after-free in __locks_delete_block __locks_delete_block locks_delete_block ksmbd_vfs_posix_lock_unblock smb2_remove_blocked_lock smb2_cancel <- 2nd SMB2_CANCEL fires cancel_fn handle_ksmbd_work Allocated by ...: locks_alloc_lock <- smb2_lock Freed by ...: locks_free_lock <- smb2_lock (cancelled branch) ... cache file_lock_cache of size 192 Reproduced on mainline with KASAN by an authenticated SMB client. Skip a work whose state is already KSMBD_WORK_CANCELLED so its cancel callback cannot be fired a second time.

Gravité et risque d'exploitation

CVE-2026-53198 obtient un score CVSS de 8.8/10, soit une gravité élevée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.45 %, ce qui la place devant 37.3 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <=6.1.*, <=7.0.*, <=6.12.*, 6.12.94, 0, <b7063c7426ea5a4d15e01b60538718765392f49d, <2b2eda2821cff1d1b5a423b6ee7d8fc6fbc8e694, <14d2eee0193ac3cd1bf3d014373449f0b8d35d6d, 6.1.176, <=6.6.*, 7.0.13, <5.15, 6.18.36, e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9, 7.1, 5.15, <=6.18.*, <0da2e073f9cbf4985a0fd9acb71bc5ff599f8afd, <f580d27e8928828693df44ba2db0fffdbe11dfea, <89ae9df09d2c1fb4a4eb495c113a7ce1dca34147, <=*, 6.6.143) est présent sur votre parc.
  • Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
  • À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
  • Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.

Références

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