CVE-2026-43366 io_uring/kbuf: check if target buffer list is still legacy on recycle
A race condition in the Linux kernel io_uring subsystem allows attackers to potentially execute arbitrary code or escalate privileges via improper buffer list recycling checks.
- 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-2026-43366?
CVE-2026-43366 is a high-severity vulnerability in Linux kernel, published on 8 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:
io_uring/kbuf: check if target buffer list is still legacy on recycle
There's a gap between when the buffer was grabbed and when it potentially gets recycled, where if the list is empty, someone could've upgraded it to a ring provided type. This can happen if the request is forced via io-wq. The legacy recycling is missing checking if the buffer_list still exists, and if it's of the correct type. Add those checks.
Weakness: CWE-362
Which versions are affected by CVE-2026-43366?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-43366?
Apply the vendor's patch.
Is CVE-2026-43366 being exploited?
There is no known exploitation of CVE-2026-43366 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-43366, DEBIAN-CVE-2026-43366, GHSA-g6hq-4292-hhwx, ROOT-OS-UBUNTU-2404-CVE-2026-43366, UBUNTU-CVE-2026-43366.