CVE-2026-53166

Summary

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

futex/requeue: Prevent NULL pointer dereference in remove_waiter() on self-deadlock

When FUTEX_CMP_REQUEUE_PI requeues a non-top waiter that already owns the target PI futex, task_blocks_on_rt_mutex() returns -EDEADLK before setting waiter->task.

The subsequent remove_waiter() in rt_mutex_start_proxy_lock() dereferences the NULL waiter->task, causing a kernel crash.

Add a self-deadlock check for non-top waiters before calling rt_mutex_start_proxy_lock(), analogous to the top-waiter check in futex_lock_pi_atomic().

Affected Software

VendorProductVersion RangeStatus
LinuxLinux3fb7394a837740770f0d6b4b30567e60786a63f2 < 16f8e17184b31382076f84751db5ac51fc02733eaffected
LinuxLinux88614876370aac8ad1050ad785a4c095ba17ac11 < 1f2f3f3eacd6653ab215c5d2ea70811148d433fcaffected
LinuxLinux3bfdc63936dd4773109b7b8c280c0f3b5ae7d349 < 74e144274af39935b0f410c0ee4d2b91c3730414affected
LinuxLinuxd8cce4773c2b23d819baf5abedc62f7b430e8745affected
LinuxLinux8a1fc8d698ac5e5916e3082a0f74450d71f9611faffected
LinuxLinux6d52dfcb2a5db86e346cf51f8fcf2071b8085166affected
LinuxLinux6.1.175 < 6.2affected
LinuxLinux6.6.140 < 6.7affected
LinuxLinux6.12.86 < 6.13affected
LinuxLinux6.18.27 < 6.18.36affected
LinuxLinux7.0.4 < 7.0.13affected

Weaknesses

References