CVE-2026-89931 KVM: nVMX: Ensure KVM_REQ_GET_NESTED_STATE_PAGES is cleared on VM-Exit
A flaw in Linux KVM nested virtualization allows a local attacker to cause a denial of service by triggering double-mapping of VMCS pages.
- 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-2026-89931?
CVE-2026-89931 is a 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:
KVM: nVMX: Ensure KVM_REQ_GET_NESTED_STATE_PAGES is cleared on VM-Exit
Always check and clear KVM_REQ_GET_NESTED_STATE_PAGES when emulating a nested VM-Exit to ensure the request is cleared, even when KVM was built with CONFIG_KVM_HYPERV=n, as KVM subtly relies on the "check" to clear the flag and thus avoid double-mapping the vmcs12 pages, e.g. if KVM manages to bail from VM-Enter without processing the request, and then emulates VMLAUNCH or VMRESUME.
Which versions are affected by CVE-2026-89931?
How do I fix CVE-2026-89931?
Apply the vendor's patch.
Is CVE-2026-89931 being exploited?
There is no known exploitation of CVE-2026-89931 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-89931, DEBIAN-CVE-2026-89931, GHSA-9jg7-wvq2-32v3, UBUNTU-CVE-2026-89931.