CVE-2026-89929

/// Technical description

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

KVM: nVM: Ensure INVVPID is emulated on the correct physical CPU

When emulating INVVPID, KVM executes INVVPID on the physical CPU using

vpid02 (instead of the L1 assigned VPID), after doing some validations

on the operands. However, it is possible that the physical CPU KVM

executes INVVPID on is different from the CPU L2 is running on.

For example, in the following scenario:

- L2 runs on CPU #1 and exits to L1 (vmx->nested.vmcs02.cpu=1)

- L1 migrates to CPU #2 and executes INVVPID

- KVM executes INVVPID on CPU #2

- L1 migrates back to CPU #1 and runs L2 (vmx->nested.vmcs02.cpu=1)

The TLB entries on CPU #1 are never invalidated, because INVVPID was

executed on CPU #2, and vmcs02 never ran on a different pCPU (i.e.

vmx_vcpu_load_vmcs() will *not* request KVM_REQ_TLB_FLUSH).

Ensure that INVVPID is being executed on the same pCPU that L2 last ran

on, and if not, fallback to clearing last_vpid=0 to trigger a full VPID

/// 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