High · CVSS 8.2CVE-2026-81627

Qemu-kvm: vapic writable rom alias can escape the option-rom window and expose locked smramCVE-2026-81627

Answer in brief

CVE-2026-81627 records a High severity (CVSS 8.2) vulnerability in Qemu-kvm: vapic writable rom alias can escape the option-rom window and expose locked smram. The current sources do not mark it as known exploited. The current feed maps Red Hat/openshift/ose-rhel-coreos-8 (generic), Red Hat/openshift/ose-rhel-coreos-9 (generic), Red Hat/qemu-kvm (generic), Red Hat/qemu-kvm-ma (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 18, 2026Updated Oct 30, 2026Source checked Nov 2, 2026First seen by HOL Sep 18, 2026Material review Oct 30, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 8.2
Exploitation: Not marked as known exploited
Affected software: 7 mapped packages or products
Fix availability: Not reported

Why this deserves its current priority

CVSS is 8.2. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Red Hat/openshift/ose-rhel-coreos-8 (generic), Red Hat/openshift/ose-rhel-coreos-9 (generic), Red Hat/qemu-kvm (generic), Red Hat/qemu-kvm-ma (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Red Hat/openshift/ose-rhel-coreos-8generic	*	Not reported
Red Hat/openshift/ose-rhel-coreos-9generic	*	Not reported
Red Hat/qemu-kvmgeneric	*	Not reported
Red Hat/qemu-kvm-mageneric	*	Not reported
Red Hat/qemu-kvm-rhevgeneric	*	Not reported
Red Hat/virt-devel:rhel/qemu-kvmgeneric	*	Not reported
Red Hat/virt:rhel/qemu-kvmgeneric	*	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Red Hat/openshift/ose-rhel-coreos-8, Red Hat/openshift/ose-rhel-coreos-9, Red Hat/qemu-kvm.
Review the reported fix. Source-reported workaround: The VAPIC TPR optimization can be disabled by preventing the kvmvapic option ROM from loading. When using libvirt, set the following in the guest's domain XML: ``` <features> <apic/> <hyperv> <vapic state='off'/> </hyperv> </features> ``` When using QEMU directly, pass `-global kvmvapic.rom=off` on the command line. This optimization is only used by 32-bit Windows guests for MMIO-based TPR register access. Linux guests, 64-bit Windows guests, and any guest using x2APIC or MSR-based TPR access are unaffected by disabling it.

Evidence timeline and material changes

Published upstream
Sep 18, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Oct 30, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 18, 2026

Sources and claim methodology

Upstream source description

A flaw was found in QEMU. The VAPIC setup hypercall in hw/i386/vapic.c does not validate that the writable RAM alias remains within the option ROM window. A privileged guest user on a Q35/KVM machine can position this alias over locked SMRAM, bypassing chipset D_LCK protection and injecting code into System Management Mode memory.

Quoted source text, attributed separately from HOL analysis.