CVE-2026-64425 io_uring/io-wq: re-check IO_WQ_BIT_EXIT for each linked work item
A race condition in the Linux kernel io_uring subsystem allows work items to continue executing after exit, potentially causing denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-64425?
CVE-2026-64425 is a medium-severity vulnerability in Linux kernel, published on 25 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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.
Which versions are affected by CVE-2026-64425?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-64425?
Apply the vendor's patch.
Is CVE-2026-64425 being exploited?
There is no known exploitation of CVE-2026-64425 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-93488, BELL-CVE-2026-64425, DEBIAN-CVE-2026-64425, GHSA-rmw8-w7cg-rwfm, ROOT-OS-UBUNTU-2204-CVE-2026-64425, UBUNTU-CVE-2026-64425.