CVE-2024-56709 io_uring: check if iowq is killed before queuing
A null pointer dereference in the Linux kernel io_uring subsystem can cause a system crash when task work is executed after termination.
- 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-2024-56709?
CVE-2024-56709 is a high-severity vulnerability in Linux kernel, published on 29 Dec 2024. 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: 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.
Which versions are affected by CVE-2024-56709?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2024-56709?
Apply the vendor's patch.
Is CVE-2024-56709 being exploited?
There is no known exploitation of CVE-2024-56709 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-68550, BELL-CVE-2024-56709, DEBIAN-CVE-2024-56709, GHSA-6mmm-fwjc-qrhc, ROOT-OS-DEBIAN-13-CVE-2024-56709, ROOT-OS-UBUNTU-2204-CVE-2024-56709 and 1 more.