CVE-2025-68333 sched_ext: Fix possible deadlock in the deferred_irq_workfn()
A race condition in the Linux kernel's sched_ext subsystem can cause a deadlock in PREEMPT_RT kernels, leading to 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-2025-68333?
CVE-2025-68333 is a medium-severity vulnerability in Linux kernel, published on 22 Dec 2025. 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:
sched_ext: Fix possible deadlock in the deferred_irq_workfn()
For PREEMPT_RT=y kernels, the deferred_irq_workfn() is executed in the per-cpu irq_work/* task context and not disable-irq, if the rq returned by container_of() is current CPU's rq, the following scenarios may occur:
lock(&rq->__lock); <Interrupt> lock(&rq->__lock);
This commit use IRQ_WORK_INIT_HARD() to replace init_irq_work() to initialize rq->scx.deferred_irq_work, make the deferred_irq_workfn() is always invoked in hard-irq context.
Weakness: CWE-667
Which versions are affected by CVE-2025-68333?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-68333?
Apply the vendor's patch.
Is CVE-2025-68333 being exploited?
There is no known exploitation of CVE-2025-68333 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2025-68333, DEBIAN-CVE-2025-68333, GHSA-xw74-3hjf-3xpv, ROOT-OS-DEBIAN-13-CVE-2025-68333, ROOT-OS-UBUNTU-2204-CVE-2025-68333, ROOT-OS-UBUNTU-2404-CVE-2025-68333 and 1 more.