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CVE-2026-89662

Vulnérabilité critique dans Linux (Linux)

CVSS 9.8 · Critique
EPSS 0.7%
Linux•Linux•Versions : <=6.1.*, 4.15.14, <=6.12.*, <4.16, 5.15.221, <42d7954b0a1907d4ef122aef94561952a033cdc3, 5.10.270, 0, 7.2.4, <4.10, 6.1.188, <5e2fa29d223a9a1e6a948e40b109d09081d1decd, 68ef3bc3166468678d5e1fdd216628c35bd1186f, e294c4c2d33b7307a89cdf31bec08a112d6a9297, <=5.10.*, <=6.6.*, <4804c58f73a80d12df1de323bf97a164f6ee8743, <bb38ff8b4dafbbd1781ad37cd96722fdf2cd972a, 6.6.157, <1ce74d1b7770e69735e8f8e509807af4ff9c8ee7, 4.14.31, <=6.18.*, 4.9.91, <=7.2.*, 4.16, <=*, <=5.15.*, 0f44e9da465ea259b6c9f31a627f3c50a16e1679, <b8bad5a11416b26cc7fd4b18fba46d75ff636558, <a6ead6fff3a7d03e49845f048f7000a2e0d34431, <8cf4ff0a7c083dd5e0067f517d63979b74b66649, 6.18.50, <4.15, 797bfd05d4040fbf766198b3cfcc1838002cc890, 6.12.109, 7.3

Description

In the Linux kernel, the following vulnerability has been resolved: NFSD: Prevent lock owner use-after-free during client teardown __destroy_client() releases a client's open owners, but a lock owner whose only reference is a blocked lock (nbl) stays on cl_ownerstr_hashtbl. client_has_state() does not count a bare owner, so DESTROY_CLIENTID can reach __destroy_client() with such owners present. __destroy_client() then walks the table, calling remove_blocked_locks() on each owner without a reference. Freeing a blocked lock drops the owner reference held via flc_owner. The per-net laundromat reaps blocked locks from nn->blocked_locks_lru independently of client state. The two paths share blocked_locks_lock only for the list splice, not the owner's lifetime. The laundromat therefore frees the owner as __destroy_client() dereferences it, a NULL dereference in remove_blocked_locks(). nfsd4_release_lockowner() holds a reference across the same call; __destroy_client() does not. Hold cl_lock across the walk, taking a reference and unhashing each owner, then drop it before remove_blocked_locks() and nfs4_put_stateowner(), which take blocked_locks_lock and cl_lock.

Gravité et risque d'exploitation

CVE-2026-89662 obtient un score CVSS de 9.8/10, soit une gravité critique. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.69 %, ce qui la place devant 52.1 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <=6.1.*, 4.15.14, <=6.12.*, <4.16, 5.15.221, <42d7954b0a1907d4ef122aef94561952a033cdc3, 5.10.270, 0, 7.2.4, <4.10, 6.1.188, <5e2fa29d223a9a1e6a948e40b109d09081d1decd, 68ef3bc3166468678d5e1fdd216628c35bd1186f, e294c4c2d33b7307a89cdf31bec08a112d6a9297, <=5.10.*, <=6.6.*, <4804c58f73a80d12df1de323bf97a164f6ee8743, <bb38ff8b4dafbbd1781ad37cd96722fdf2cd972a, 6.6.157, <1ce74d1b7770e69735e8f8e509807af4ff9c8ee7, 4.14.31, <=6.18.*, 4.9.91, <=7.2.*, 4.16, <=*, <=5.15.*, 0f44e9da465ea259b6c9f31a627f3c50a16e1679, <b8bad5a11416b26cc7fd4b18fba46d75ff636558, <a6ead6fff3a7d03e49845f048f7000a2e0d34431, <8cf4ff0a7c083dd5e0067f517d63979b74b66649, 6.18.50, <4.15, 797bfd05d4040fbf766198b3cfcc1838002cc890, 6.12.109, 7.3) 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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