CVE-2026-98716: KVM: SVM: Use the active VMCB's MSR bitmap when checking if MSR is intercepted

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: 2026-10-18 · updated 2026-10-30

Description

In the Linux kernel, the following vulnerability has been resolved: KVM: SVM: Use the active VMCB's MSR bitmap when checking if MSR is intercepted Use the MSR permission bitmap of the active VMCB instead of assuming that KVM is always using vmcb02's bitmap when L2 is active, as KVM uses msrpm02 if and only if L1 wants to intercept MSR accesses, i.e. if and only if KVM needs to merge msprm01 with msrpm12. Don't bother tracking the virtual address of the bitmap that's being used, as __va() is cheap on x86, and caching the virtual address would introduce yet another source of potentially stale information.

Affected products

Linux: from 3.16.57 before 3.17; from 4.4.168 before 4.5 — fixed in 3.17, 4.5

How to fix

Upgrade to a fixed version: Linux 3.17, 4.5. Check the vendor advisory for mitigations.

References

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