CVE-2026-64425

MEDIUMCVSS 5.5/10EPSS 0.12%

Last modified

CVE-2026-64425 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. 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. EPSS estimates a 0.12% chance of exploitation in the next 30 days.

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.

Metrics

EPSS Probability
0.12%

2.3th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

VendorProductVersions
LinuxLinux Kernel>= 5.10.253, < 5.10.261
LinuxLinux Kernel>= 5.15.203, < 5.15.212
LinuxLinux Kernel>= 6.1.167, < 6.1.178
LinuxLinux Kernel>= 6.6.122, < 6.6.145
LinuxLinux Kernel>= 6.12.68, < 6.12.96
LinuxLinux Kernel>= 6.18.8, < 6.18.39
LinuxLinux Kernel>= 6.19.1, < 7.1.4
LinuxLinux Kernel6.19

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2026-64425?
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.
How severe is CVE-2026-64425?
CVE-2026-64425 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.12% probability of exploitation in the next 30 days.
How do I fix CVE-2026-64425?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST