CVE-2024-56709: io_uring: check if iowq is killed before queuing

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-12-29 · updated 2026-08-04

Description

In the Linux kernel, the following vulnerability has been resolved: io_uring: check if iowq is killed before queuing task work can be executed after the task has gone through io_uring termination, whether it's the final task_work run or the fallback path. In this case, task work will find ->io_wq being already killed and null'ed, which is a problem if it then tries to forward the request to io_queue_iowq(). Make io_queue_iowq() fail requests in this case. Note that it also checks PF_KTHREAD, because the user can first close a DEFER_TASKRUN ring and shortly after kill the task, in which case ->iowq check would race.

Affected products

Linux kernel: from 5.14.1 before 6.1.122; from 6.2 before 6.6.68; from 6.7 before 6.12.7; 5.14, 5.14-rc4, 5.14-rc5, 5.14-rc6, 5.14-rc7, 6.13-rc1 (+2) — fixed in 6.1.122, 6.12.7, 6.6.68

How to fix

Upgrade to a fixed version: Linux kernel 6.1.122, 6.12.7, 6.6.68. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2024-56709 or the next vulnerability affects your stack