CVE-2026-45987

/// Technical description

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

KVM: nSVM: Sync interrupt shadow to cached vmcb12 after VMRUN of L2

After VMRUN in guest mode, nested_sync_control_from_vmcb02() syncs

fields written by the CPU from vmcb02 to the cached vmcb12. This is

because the cached vmcb12 is used as the authoritative copy of some of

the controls, and is the payload when saving/restoring nested state.

int_state is also written by the CPU, specifically bit 0 (i.e.

SVM_INTERRUPT_SHADOW_MASK) for nested VMs, but it is not sync'd to

cached vmcb12. This does not cause a problem if KVM_SET_NESTED_STATE

preceeds KVM_SET_VCPU_EVENTS in the restore path, as an interrupt shadow

would be correctly restored to vmcb02 (KVM_SET_VCPU_EVENTS overwrites

what KVM_SET_NESTED_STATE restored in int_state).

However, if KVM_SET_VCPU_EVENTS preceeds KVM_SET_NESTED_STATE, an

interrupt shadow would be restored into vmcb01 instead of vmcb02. This

would mostly be benign for L1 (delays an interrupt), but

/// 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