CVE-2026-68081

Technical Description

In the Linux kernel, the following vulnerability has been resolved:

KVM: nVMX: Put vmcs12 pages if nested VM-Enter fails due to invalid guest state

Put all vmcs12 pages if KVM synthesizes a nested VM-Exit due to invalid

guest while emulating VMLAUNCH or VMRESUME. The invalid guest state path

doesn't use nested_vmx_vmexit() as that API is intended to be used if and

only if L2 is active, and the open coded equivalent neglects to put the

vmcs12 pages. Failure to put the vmcs12 pages leaks any pinned pages

(and/or mappings) if L1 retries VMLAUNCH/VMRESUME.

Note, the !from_vmenter scenario doesn't suffer the same problem, as

vmx_get_nested_state_pages() only gets/pins/maps the vmcs12 pages if L2 is

active, i.e. if a "full" VM-Exit is guaranteed before KVM will retry

getting vmcs12 pages.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References