CVE-2026-98390 x86/amd_node: Avoid divide by zero on virtualized systems
A divide-by-zero error in the Linux kernel x86/amd_node module causes a crash on virtualized systems, leading to denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-98390?
CVE-2026-98390 is a denial of service vulnerability in Linux, published on 14 Oct 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:
x86/amd_node: Avoid divide by zero on virtualized systems
On a virtualized system, the number of nodes does not have a relationship to the number of roots. A Xen PVH dom0 can calculate roots_per_node as 0, which crashes with a divide by zero in:
if (count++ % roots_per_node)
because the underlying topology code on Xen ends up making num_nodes 2 and num_roots 1 and the integer division result is 0.
The issue is seen with Xen, but it could affect other systems.
Set roots_per_node to 1 in this case. Print a firmware bug when this is performed for non-virtualized systems.
[ bp: Massage commit message. ]
Which versions are affected by CVE-2026-98390?
How do I fix CVE-2026-98390?
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-2026-98390 being exploited?
There is no known exploitation of CVE-2026-98390 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-98390, DEBIAN-CVE-2026-98390, GHSA-fx97-gm68-7q96, UBUNTU-CVE-2026-98390.