CVE-2026-43400 drm/amdgpu: add upper bound check on user inputs in signal ioctl
A missing upper bound check in the amdgpu signal ioctl allows attackers to trigger out-of-memory conditions, causing 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-2026-43400?
CVE-2026-43400 is a medium-severity denial of service 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:
drm/amdgpu: add upper bound check on user inputs in signal ioctl
Huge input values in amdgpu_userq_signal_ioctl can lead to a OOM and could be exploited.
So check these input value against AMDGPU_USERQ_MAX_HANDLES which is big enough value for genuine use cases and could potentially avoid OOM.
(cherry picked from commit be267e15f99bc97cbe202cd556717797cdcf79a5)
Which versions are affected by CVE-2026-43400?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-43400?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-43400 being exploited?
There is no known exploitation of CVE-2026-43400 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-86181, BELL-CVE-2026-43400, DEBIAN-CVE-2026-43400, GHSA-q4g6-xq34-4jxw, ROOT-OS-UBUNTU-2204-CVE-2026-43400, ROOT-OS-UBUNTU-2404-CVE-2026-43400 and 1 more.