{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-43133", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-05-01T14:12:55.988Z", "datePublished": "2026-05-06T11:27:20.882Z", "dateUpdated": "2026-09-01T12:04:42.269Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:26:09.214Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: nSVM: Always use vmcb01 in VMLOAD/VMSAVE emulation\n\nCommit cc3ed80ae69f (\"KVM: nSVM: always use vmcb01 to for vmsave/vmload\nof guest state\") made KVM always use vmcb01 for the fields controlled by\nVMSAVE/VMLOAD, but it missed updating the VMLOAD/VMSAVE emulation code\nto always use vmcb01.\n\nAs a result, if VMSAVE/VMLOAD is executed by an L2 guest and is not\nintercepted by L1, KVM will mistakenly use vmcb02. Always use vmcb01\ninstead of the current VMCB." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H", "baseScore": 7.9, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The vulnerable path is reached by locally running a KVM vCPU through /dev/kvm and executing nested SVM VMLOAD/VMSAVE from an L2 guest; it is not reachable via network packets.\nAC:L - The trigger is deterministic once nested SVM is available: configure L1 not to intercept VMLOAD/VMSAVE and execute the instruction in L2. No race or attacker-uncontrolled timing condition is required.\nPR:L - The attacker needs the ability to create/run a KVM VM or execute code in a nested guest, which is local low privilege where /dev/kvm is delegated. No real init-namespace root capability is required by the vulnerable emulation path itself.\nUI:N - After the VM/nested guest is running, exploitation is triggered solely by guest instruction execution. No additional victim user action is required.\nS:C - The bug is in KVM’s enforcement of the nested virtualization boundary, where L2 execution causes KVM to operate on the wrong L0-maintained VMCB state. That can affect resources outside the L2 guest’s own security authority.\nC:L - VMSAVE can copy bounded VMLOAD/VMSAVE save-state fields from the wrong internal VMCB into guest-accessible memory. I did not identify an arbitrary host-memory read primitive, so the defensible confidentiality impact is limited.\nI:L - VMLOAD can corrupt a bounded set of VMLOAD/VMSAVE state fields in the wrong KVM VMCB, causing incorrect nested guest/L1 state handling. I did not find a direct arbitrary host write or host code execution primitive.\nA:H - The wrong VMCB state can make nested VM execution fail or crash/hang the affected virtual machine/vCPU, and the attacker can trigger it repeatedly. This is a complete availability impact for the affected nested virtualization workload, even though I did not find a host kernel panic path." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "arch/x86/kvm/svm/svm.c" ], "versions": [ { "version": "cc3ed80ae69f454c3d904af9f65394a540099723", "lessThan": "10063e1251c1485034a018236080792ad083dcc5", "status": "affected", "versionType": "git" }, { "version": "cc3ed80ae69f454c3d904af9f65394a540099723", "lessThan": "c3b7015000988ba35ecd5648f4b2283960f00543", "status": "affected", "versionType": "git" }, { "version": "cc3ed80ae69f454c3d904af9f65394a540099723", "lessThan": "3880e331b0b31d0d5d3702b124f6c93539cd478a", "status": "affected", "versionType": "git" }, { "version": "cc3ed80ae69f454c3d904af9f65394a540099723", "lessThan": "fce2fd4a2ca05670a91015aacccf96a1c26268fd", "status": "affected", "versionType": "git" }, { "version": "cc3ed80ae69f454c3d904af9f65394a540099723", "lessThan": "d464cf1ed900d47c85393d40b00017b6adfc2e6c", "status": "affected", "versionType": "git" }, { "version": "cc3ed80ae69f454c3d904af9f65394a540099723", "lessThan": "0004ecb798b30e90d7ebfe74efae2d9423315a64", "status": "affected", "versionType": "git" }, { "version": "cc3ed80ae69f454c3d904af9f65394a540099723", "lessThan": "127ccae2c185f62e6ecb4bf24f9cb307e9b9c619", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "arch/x86/kvm/svm/svm.c" ], "versions": [ { "version": "5.13", "status": "affected" }, { "version": "0", "lessThan": "5.13", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.202", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.165", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.128", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.75", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.16", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19.6", "lessThanOrEqual": "6.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.13", "versionEndExcluding": "5.15.202" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.13", "versionEndExcluding": "6.1.165" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.13", "versionEndExcluding": "6.6.128" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.13", "versionEndExcluding": "6.12.75" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.13", "versionEndExcluding": "6.18.16" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.13", "versionEndExcluding": "6.19.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.13", "versionEndExcluding": "7.0" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/10063e1251c1485034a018236080792ad083dcc5" }, { "url": "https://git.kernel.org/stable/c/c3b7015000988ba35ecd5648f4b2283960f00543" }, { "url": "https://git.kernel.org/stable/c/3880e331b0b31d0d5d3702b124f6c93539cd478a" }, { "url": "https://git.kernel.org/stable/c/fce2fd4a2ca05670a91015aacccf96a1c26268fd" }, { "url": "https://git.kernel.org/stable/c/d464cf1ed900d47c85393d40b00017b6adfc2e6c" }, { "url": "https://git.kernel.org/stable/c/0004ecb798b30e90d7ebfe74efae2d9423315a64" }, { "url": "https://git.kernel.org/stable/c/127ccae2c185f62e6ecb4bf24f9cb307e9b9c619" } ], "title": "KVM: nSVM: Always use vmcb01 in VMLOAD/VMSAVE emulation", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "affected": [ { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/o:redhat:enterprise_linux:10" ], "defaultStatus": "affected", "packageName": "kernel", "product": "Red Hat Enterprise Linux 10", "vendor": "Red Hat" }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/o:redhat:enterprise_linux:10" ], "defaultStatus": "unaffected", "packageName": "libkrun", "product": "Red Hat Enterprise Linux 10", "vendor": "Red Hat" }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/o:redhat:enterprise_linux:6" ], "defaultStatus": "unaffected", "packageName": "kernel", "product": "Red Hat Enterprise Linux 6", "vendor": "Red Hat" }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/o:redhat:enterprise_linux:7" ], "defaultStatus": "unaffected", "packageName": "kernel", "product": "Red Hat Enterprise Linux 7", "vendor": "Red Hat" }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/o:redhat:enterprise_linux:7" ], "defaultStatus": "unaffected", "packageName": "kernel-rt", "product": "Red Hat Enterprise Linux 7", "vendor": "Red Hat" }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/o:redhat:enterprise_linux:8" ], "defaultStatus": "affected", "packageName": "kernel", "product": "Red Hat Enterprise Linux 8", "vendor": "Red Hat" }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/o:redhat:enterprise_linux:8" ], "defaultStatus": "affected", "packageName": "kernel-rt", "product": "Red Hat Enterprise Linux 8", "vendor": "Red Hat" }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/o:redhat:enterprise_linux:9" ], "defaultStatus": "affected", "packageName": "kernel", "product": "Red Hat Enterprise Linux 9", "vendor": "Red Hat" }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/o:redhat:enterprise_linux:9" ], "defaultStatus": "unknown", "packageName": "kernel-rt", "product": "Red Hat Enterprise Linux 9", "vendor": "Red Hat" }, { "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": [ "cpe:/a:redhat:openshift:4" ], "defaultStatus": "affected", "packageName": "openshift/ose-rhel-coreos-9", "product": "Red Hat OpenShift Container Platform 4", "vendor": "Red Hat" } ], "datePublic": "2026-05-06T00:00:00.000Z", "descriptions": [ { "lang": "en", "value": "A flaw was found in the Linux kernel's Kernel-based Virtual Machine (KVM) nSVM module. When a nested virtual machine (L2 guest) executes VMSAVE/VMLOAD instructions, and these are not intercepted by the first-level hypervisor (L1), KVM incorrectly uses `vmcb02` instead of `vmcb01` for managing guest state. This incorrect Virtual Machine Control Block (VMCB) handling could lead to unexpected behavior or state corruption within the virtualized environment." } ], "metrics": [ { "other": { "content": { "namespace": "https://access.redhat.com/security/updates/classification/", "value": "Important" }, "type": "Red Hat severity rating" } }, { "cvssV3_1": { "attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.9, "baseSeverity": "HIGH", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "privilegesRequired": "LOW", "scope": "CHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H", "version": "3.1" }, "format": "CVSS" } ], "problemTypes": [ { "descriptions": [ { "cweId": "CWE-628", "description": "Function Call with Incorrectly Specified Arguments", "lang": "en", "type": "CWE" } ] } ], "references": [ { "tags": [ "vdb-entry", "x_refsource_REDHAT" ], "url": "https://access.redhat.com/security/cve/CVE-2026-43133" }, { "name": "RHBZ#2467065", "tags": [ "issue-tracking", "x_refsource_REDHAT" ], "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2467065" }, { "tags": [ "x_sadp-csaf-vex" ], "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-43133.json" } ], "timeline": [ { "lang": "en", "time": "2026-05-06T00:00:00.000Z", "value": "Reported to Red Hat." }, { "lang": "en", "time": "2026-05-06T00:00:00.000Z", "value": "Made public." } ], "title": "kernel: KVM: nSVM: Always use vmcb01 in VMLOAD/VMSAVE emulation", "x_adpType": "supplier", "x_generator": { "engine": "sadp-cli 1.0.0" }, "providerMetadata": { "orgId": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "shortName": "redhat-SADP", "dateUpdated": "2026-09-01T12:04:42.269Z" } } ] } }