CVE-2026-46210 media: iris: fix use-after-free of fmt_src during MBPF check
A race condition in the Linux kernel iris media driver allows a use-after-free, potentially enabling local attackers to execute code or escalate privileges.
- 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-2026-46210?
CVE-2026-46210 is a high-severity use after free vulnerability in Linux kernel, published on 28 May 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:
media: iris: fix use-after-free of fmt_src during MBPF check
During concurrency testing, multiple instances can run in parallel, and each instance uses its own inst->lock while the core->lock protects the list of active instances. The race happens because these locks cover different scopes, inst->lock protects only the internals of a single instance, while the Macro Blocks Per Frame (MBPF) checker walks the core list under core->lock and reads fields like fmt_src->width and fmt_src->height. At the same time, iris_close() may free fmt_src and fmt_dst under inst->lock while the instance is still present in the core list. This allows a situation where the MBPF checker, still iterating through the core list, reaches an instance whose fmt_src was already freed by another thread and ends up dereferencing a dangling pointer, resulting in a use-after-free. This happens because the MBPF checker assumes that any instance in the core list is fully valid, but the freeing of fmt_src and fmt_dst without removing the instance from the core list is not correct.
The correct ordering is to defer freeing fmt_src and fmt_dst until after the instance has been removed from the core list and all teardown under the core lock has completed, ensuring that no dangling pointers are ever exposed during MBPF checks.
Weakness: CWE-416
Which versions are affected by CVE-2026-46210?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-46210?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-46210 being exploited?
There is no known exploitation of CVE-2026-46210 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-46210, DEBIAN-CVE-2026-46210, GHSA-v3mx-wgxp-826p, UBUNTU-CVE-2026-46210.