{"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":"2026-09-15T12:04:27.795Z"},"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:10.2"],"defaultStatus":"affected","packageName":"kernel","product":"Red Hat Enterprise Linux 10","vendor":"Red Hat","versions":[{"lessThan":"*","status":"unaffected","version":"0:6.12.0-211.53.1.el10_2","versionType":"rpm"}]},{"collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:enterprise_linux:9","cpe:/o:redhat:enterprise_linux:9"],"defaultStatus":"affected","packageName":"kernel","product":"Red Hat Enterprise Linux 9","vendor":"Red 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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":"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-8","product":"Red Hat OpenShift Container Platform 4","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"},{"tags":["vendor-advisory","x_refsource_REDHAT"],"url":"https://access.redhat.com/errata/RHSA-2026:66357"},{"tags":["vendor-advisory","x_refsource_REDHAT"],"url":"https://access.redhat.com/errata/RHSA-2026:65334"},{"tags":["vendor-advisory","x_refsource_REDHAT"],"url":"https://access.redhat.com/errata/RHSA-2026:66180"},{"tags":["vendor-advisory","x_refsource_REDHAT"],"url":"https://access.redhat.com/errata/RHSA-2026:67468"},{"tags":["vendor-advisory","x_refsource_REDHAT"],"url":"https://access.redhat.com/errata/RHSA-2026:67469"}],"solutions":[{"lang":"en","value":"RHSA-2026:66357: Red Hat OpenShift Container Platform 4.22"},{"lang":"en","value":"RHSA-2026:65334: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10), Red Hat Enterprise Linux Real Time (v. 10), Red Hat Enterprise Linux Real Time for NFV (v. 10)"},{"lang":"en","value":"RHSA-2026:66180: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux BaseOS (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9), Red Hat Enterprise Linux Real Time (v. 9), Red Hat Enterprise Linux Real Time for NFV (v. 9)"},{"lang":"en","value":"RHSA-2026:67468: Red Hat Enterprise Linux BaseOS (v. 8), Red Hat Enterprise Linux CRB (v. 8)"},{"lang":"en","value":"RHSA-2026:67469: Red Hat Enterprise Linux NFV (v. 8), Red Hat Enterprise Linux RT (v. 8)"}],"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","workarounds":[{"lang":"en","value":"Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability."}],"x_adpType":"supplier","x_generator":{"engine":"sadp-cli 1.0.0"},"providerMetadata":{"orgId":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c","shortName":"redhat-SADP","dateUpdated":"2026-09-15T12:04:27.795Z"}}]}}