{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-81627","assignerOrgId":"53f830b8-0a3f-465b-8143-3b8a9948e749","state":"PUBLISHED","assignerShortName":"redhat","dateReserved":"2026-08-27T09:01:09.972Z","datePublished":"2026-09-18T10:54:03.297Z","dateUpdated":"2026-10-30T20:05:12.889Z"},"containers":{"cna":{"title":"Qemu-kvm: vapic writable rom alias can escape the option-rom window and expose locked smram","metrics":[{"other":{"content":{"value":"Important","namespace":"https://access.redhat.com/security/updates/classification/"},"type":"Red Hat severity rating"}},{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"LOCAL","availabilityImpact":"HIGH","baseScore":8.2,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"HIGH","scope":"CHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H","version":"3.1"},"format":"CVSS"}],"descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 10","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"qemu-kvm","defaultStatus":"affected","cpes":["cpe:/o:redhat:enterprise_linux:10"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 6","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"qemu-kvm","defaultStatus":"unaffected","cpes":["cpe:/o:redhat:enterprise_linux:6"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 7","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"qemu-kvm","defaultStatus":"affected","cpes":["cpe:/o:redhat:enterprise_linux:7"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 7","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"qemu-kvm-ma","defaultStatus":"affected","cpes":["cpe:/o:redhat:enterprise_linux:7"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 8","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"virt-devel:rhel/qemu-kvm","defaultStatus":"affected","cpes":["cpe:/o:redhat:enterprise_linux:8"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 8","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"virt:rhel/qemu-kvm","defaultStatus":"affected","cpes":["cpe:/o:redhat:enterprise_linux:8"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 9","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"qemu-kvm","defaultStatus":"affected","cpes":["cpe:/o:redhat:enterprise_linux:9"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux for NVIDIA 26","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"qemu-kvm","defaultStatus":"unknown","cpes":["cpe:/a:redhat:enterprise_linux_nvidia:"]},{"vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 4","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"openshift/ose-rhel-coreos-8","defaultStatus":"affected","cpes":["cpe:/a:redhat:openshift:4"]},{"vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 4","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"openshift/ose-rhel-coreos-9","defaultStatus":"affected","cpes":["cpe:/a:redhat:openshift:4"]},{"vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 5","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"openshift/ose-rhel-coreos-9","defaultStatus":"affected","cpes":["cpe:/a:redhat:openshift:5"]},{"vendor":"Red Hat","product":"Red Hat OpenStack Platform 13 (Queens)","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"qemu-kvm-rhev","defaultStatus":"affected","cpes":["cpe:/a:redhat:openstack:13"]}],"references":[{"url":"https://access.redhat.com/security/cve/CVE-2026-81627","tags":["vdb-entry","x_refsource_REDHAT"]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2536950","name":"RHBZ#2536950","tags":["issue-tracking","x_refsource_REDHAT"]},{"url":"https://gitlab.com/qemu-project/qemu/-/work_items/4206"}],"datePublic":"2026-08-26T00:00:00.000Z","problemTypes":[{"descriptions":[{"cweId":"CWE-787","description":"Out-of-bounds Write","lang":"en","type":"CWE"}]}],"x_redhatCweChain":"CWE-787: Out-of-bounds Write","workarounds":[{"lang":"en","value":"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:\n```\n<features>\n  <apic/>\n  <hyperv>\n    <vapic state='off'/>\n  </hyperv>\n</features>\n```\nWhen using QEMU directly, pass `-global kvmvapic.rom=off` on the command line.\n\nThis 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."}],"timeline":[{"lang":"en","time":"2026-09-18T00:00:00.000Z","value":"Reported to Red Hat."},{"lang":"en","time":"2026-08-26T00:00:00.000Z","value":"Made public."}],"credits":[{"lang":"en","value":"Red Hat would like to thank Artem Dinaburg (Trail of Bits) for reporting this issue."}],"providerMetadata":{"orgId":"53f830b8-0a3f-465b-8143-3b8a9948e749","shortName":"redhat","dateUpdated":"2026-10-30T20:05:12.889Z"},"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"references":[{"url":"https://gitlab.com/qemu-project/qemu/-/work_items/4206","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-18T15:07:17.054544Z","id":"CVE-2026-81627","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-09-18T15:07:23.968Z"}}]}}