CVE-2026-89818 drm/amdgpu/vcn: fix integer overflow in dec_msg buffer count check
An integer overflow in the AMD GPU VCN driver allows attackers to bypass buffer bounds checks, potentially leading to memory corruption or system crashes.
- 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-2026-89818?
CVE-2026-89818 is a high-severity vulnerability in Linux, published on 16 Sep 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/vcn: fix integer overflow in dec_msg buffer count check
If the supplied msg[2] (num_buffers) is 0x3FFFFFFF, the expression 6 + num_buffers * 4 wraps to 2 and the bounds check passes, letting the parser loop far past the end of the message BO. Triggering it additionally requires a ~4GiB mapping so that msg[1] survives the earlier "header does not fit in BO" check.
Rewrite the test in division form, which is overflow-free by construction. Also update the message to reflect that msg is invalid.
Which versions are affected by CVE-2026-89818?
How do I fix CVE-2026-89818?
Apply the vendor's patch.
Is CVE-2026-89818 being exploited?
There is no known exploitation of CVE-2026-89818 in the wild and no public exploit code.
Sources
Also known as AZL-101156, BELL-CVE-2026-89818, DEBIAN-CVE-2026-89818, GHSA-vg7q-4fvq-5g86, UBUNTU-CVE-2026-89818.