CVE-2026-98390: x86/amd_node: Avoid divide by zero on virtualized systems

Severity: unknown
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-14 · updated 2026-10-19

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. ]

Affected products

Linux kernel: from 6.17.8 before 6.18; 6.18 — fixed in 6.18, 7.3

How to fix

Upgrade to a fixed version: Linux kernel 6.18, 7.3. Check the vendor advisory for mitigations.

References

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