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CVE-2026-53399

Vulnérabilité critique dans Linux (Linux)

CVSS 9.8 · Critique
EPSS 0.5%
Linux•Linux•Versions : <30d55c8aabb261bc3f427d6b9aae7ef6206063f9, <=6.1.*, <=6.12.*, <7bbb7ce74051c8be4b69ff44ce3db370600dae61, 6.18.39, 0, <d788ef40a7517d22c97ab01700e4ae4c611b6f2f, <=7.1.*, <4.0, 6.1.178, <=5.10.*, <2e0a5d6d62600b8c614d1b55e50ef94035d6adf9, <=6.6.*, 4.0, <=6.18.*, 5.15.212, 6.6.145, 5.10.261, <8dee7c278f1c2b5bb80e17a6281c3812fc8b0cdd, <d369e5edfaaf83a448016e2f1da392b2174be801, <=*, <48a586e382e4db1dbf958d44b63e081df5f8ed04, <=5.15.*, <83c2b7797742339bb768f83935f7ca33950db138, 7.1.3, c5c707f96fc9a6e5a57ca5baac892673270abe3d, 6.12.96, 7.2

Description

In the Linux kernel, the following vulnerability has been resolved: nfsd: release layout stid on setlease failure nfs4_alloc_stid() publishes the new stid into cl->cl_stateids via idr_alloc_cyclic() under cl_lock before returning to nfsd4_alloc_layout_stateid(). When nfsd4_layout_setlease() then fails, the error path frees the layout stateid directly with kmem_cache_free() without ever calling idr_remove(), leaving the IDR slot pointing at freed slab memory. Any subsequent IDR walker (states_show, client teardown) dereferences the dangling pointer. The correct teardown for an IDR-published stid is nfs4_put_stid(), which removes the IDR slot under cl_lock, dispatches sc_free (nfsd4_free_layout_stateid) to release ls->ls_file via nfsd4_close_layout(), and drops the nfs4_file reference in its tail. A second issue blocks that switch: nfsd4_free_layout_stateid() unconditionally inspects ls->ls_fence_work via delayed_work_pending() under ls_lock, but INIT_DELAYED_WORK(&ls->ls_fence_work, ...) currently runs only after the setlease call. On the setlease-failure path the destructor would touch an uninitialized delayed_work. nfsd4_alloc_layout_stateid() nfs4_alloc_stid() /* idr_alloc_cyclic under cl_lock */ nfsd4_layout_setlease() /* fails */ nfs4_put_stid() nfsd4_free_layout_stateid() delayed_work_pending(&ls->ls_fence_work) /* needs INIT */ nfsd4_close_layout() /* nfsd_file_put(ls->ls_file) */ put_nfs4_file() Fix by hoisting the ls_fenced / ls_fence_delay / INIT_DELAYED_WORK initialization above the nfsd4_layout_setlease() call, and replace the manual nfsd_file_put + put_nfs4_file + kmem_cache_free cleanup with a single nfs4_put_stid(stp).

Gravité et risque d'exploitation

CVE-2026-53399 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 0.54 %, ce qui la place devant 44.1 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <30d55c8aabb261bc3f427d6b9aae7ef6206063f9, <=6.1.*, <=6.12.*, <7bbb7ce74051c8be4b69ff44ce3db370600dae61, 6.18.39, 0, <d788ef40a7517d22c97ab01700e4ae4c611b6f2f, <=7.1.*, <4.0, 6.1.178, <=5.10.*, <2e0a5d6d62600b8c614d1b55e50ef94035d6adf9, <=6.6.*, 4.0, <=6.18.*, 5.15.212, 6.6.145, 5.10.261, <8dee7c278f1c2b5bb80e17a6281c3812fc8b0cdd, <d369e5edfaaf83a448016e2f1da392b2174be801, <=*, <48a586e382e4db1dbf958d44b63e081df5f8ed04, <=5.15.*, <83c2b7797742339bb768f83935f7ca33950db138, 7.1.3, c5c707f96fc9a6e5a57ca5baac892673270abe3d, 6.12.96, 7.2) 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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