CVE-2026-64425: Linux Kernel

Medium severity, CVSS 5.5. EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: io_uring/io-wq: re-check IO_WQ_BIT_EXIT for each linked work item commit 10dc95939817 ("io_uring/io-wq: check IO_WQ_BIT_EXIT inside work run loop") fixed the obvious case where io_worker_handle_work() took one exit-bit snapshot before draining pending work, but the fix stops one level too early. io_worker_handle_work() now re-checks IO_WQ_BIT_EXIT in its outer work run loop, yet it still snapshots that bit once before processing a whole dependent linked-work chain. If io_wq_exit_start() sets IO_WQ_BIT_EXIT after the first linked item has started, the remaining linked items can still reuse stale do_kill = false, skip IO_WQ_WORK_CANCEL, and continue running after exit has begun. Move the check further inside, so it covers linked items too. Note: this is a syzbot special as it loves setting up tons of slow linked work on weird devices like msr that take forever to read, and immediately close the ring. Exit then takes a long time.

Affected products

• Linux Linux Kernel: from 5.10.253, before 5.10.261 (fixed in 5.10.261); from 5.15.203, before 5.15.212 (fixed in 5.15.212); from 6.1.167, before 6.1.178 (fixed in 6.1.178); from 6.6.122, before 6.6.145 (fixed in 6.6.145); from 6.12.68, before 6.12.96 (fixed in 6.12.96); from 6.18.8, before 6.18.39 (fixed in 6.18.39); …

Published 2026-07-25. Last modified 2026-09-08.