CVE-2026-64560

Technical Description

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

posix-cpu-timers: Prevent UAF caused by non-leader exec() race

Wongi and Jungwoo decoded and reported a non-leader exec() related race

which can result in an UAF:

sys_timer_delete() exec()

posix_cpu_timer_del()

// Observes old leader

p = pid_task(pid, pid_type); de_thread()

switch_leader();

release_task(old_leader)

__exit_signal(old_leader)

sighand = lock(old_leader, sighand);

posix_cpu_timers*_exit();

sighand = lock_task_sighand(p) unhash_task(old_leader);

sh = lock(p, sighand) old_leader->sighand = NULL;

unlock(sighand);

(p->sighand == NULL)

unlock(sh)

return NULL;

// Returns without action

if(!sighand)

return 0;

free_posix_timer();

This is "harmless" unless the deleted timer was armed and enqueued in

p->signal because on exec() a TGID targeted timer is inherited.

As sys_timer_delete() freed th

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References