CVE-2026-80778

CVE-2026-80778 · futex/pi: Reject cross-mm private futex owners

Cette page présente des faits issus de sources publiques. Consultez l’avis original avant toute mise à jour.

Cette page présente une partie des faits des sources. Consultez les avis liés pour la description complète et les versions concernées.

In the Linux kernel, the following vulnerability has been resolved: futex/pi: Reject cross-mm private futex owners A private futex key borrows the waiter's mm without taking an mm_users reference. Nevertheless, attach_to_pi_owner() currently accepts an owner from a different address space and copies the private key into the owner's PI state. When that owner exits, exit_pi_state_list() uses the saved key to find the hash bucket and acquires a reference to the waiter's private hash. If the last user of the waiter's mm exits concurrently, futex_hash_free() frees the hash while the owner still uses its bucket and reference. Prevent this by validating in attach_to_pi_owner() that, for private futexes, the owner mm and waiter mm are the same. Perform the check with the owner's pi_lock held and after validating owner::futex::state to serialize against a concurrent PI-state exit cleanup. [ tglx: Amended comment ]

EPSS 0,2% · Correctif disponible

Publication

2026-09-04T15:12:50.117Z

Mise à jour

2026-10-19T08:43:33.681Z

Pile logicielle: system

Vérifiez votre serveur →