CVE-2025-39977

Опубликовано: 15 окт. 2025

Источник: nvd

EPSS Низкий

Описание

In the Linux kernel, the following vulnerability has been resolved:

futex: Prevent use-after-free during requeue-PI

syzbot managed to trigger the following race:

T1 T2

futex_wait_requeue_pi() futex_do_wait() schedule() futex_requeue() futex_proxy_trylock_atomic() futex_requeue_pi_prepare() requeue_pi_wake_futex() futex_requeue_pi_complete() /* preempt */

* timeout/ signal wakes T1 *

futex_requeue_pi_wakeup_sync() // Q_REQUEUE_PI_LOCKED futex_hash_put() // back to userland, on stack futex_q is garbage

/* back */ wake_up_state(q->task, TASK_NORMAL);

In this scenario futex_wait_requeue_pi() is able to leave without using futex_q::lock_ptr for s

Ссылки

EPSS

Процентиль: 5%

0.00024

Низкий

Дефекты

Связанные уязвимости

CVE-2025-39977

ubuntu

21 день назад

In the Linux kernel, the following vulnerability has been resolved: futex: Prevent use-after-free during requeue-PI syzbot managed to trigger the following race: T1 T2 futex_wait_requeue_pi() futex_do_wait() schedule() futex_requeue() futex_proxy_trylock_atomic() futex_requeue_pi_prepare() requeue_pi_wake_futex() futex_requeue_pi_complete() /* preempt */ * timeout/ signal wakes T1 * futex_requeue_pi_wakeup_sync() // Q_REQUEUE_PI_LOCKED futex_hash_put() // back to userland, on stack futex_q is garbage /* back */ wake_up_state(q->task, TASK_NORMAL); In this scenario futex_wait_requeue_pi() is able to leave without using futex_q::lock_ptr for synchronization. This can be prevented by reading futex_q::task before updating the futex_q::requeue_state. A reference on the task_struct is not needed because requeue_pi_wake_futex() is invoked with a spinlock_t held which implies a RCU read section. Even if T1 terminates immediately after, the task_struct will rema...