{"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": "2026-09-18T10:58:39.337Z"}, "containers": {"cna": {"title": "Qemu-kvm: vapic writable rom alias can escape the option-rom window and expose locked smram", "metrics": [{"other": {"content": {"value": "Moderate", "namespace": "https://access.redhat.com/security/updates/classification/"}, "type": "Red Hat severity rating"}}, {"cvssV3_1": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 6.7, "baseSeverity": "MEDIUM", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "HIGH", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/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 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": "2026-09-18T10:58:39.337Z"}, "x_generator": {"engine": "cvelib 1.8.0"}}}}

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