{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2021-46978","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2024-02-27T18:42:55.944Z","datePublished":"2024-02-28T08:13:09.106Z","dateUpdated":"2026-05-11T13:45:35.377Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-05-11T13:45:35.377Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: nVMX: Always make an attempt to map eVMCS after migration\n\nWhen enlightened VMCS is in use and nested state is migrated with\nvmx_get_nested_state()/vmx_set_nested_state() KVM can't map evmcs\npage right away: evmcs gpa is not 'struct kvm_vmx_nested_state_hdr'\nand we can't read it from VP assist page because userspace may decide\nto restore HV_X64_MSR_VP_ASSIST_PAGE after restoring nested state\n(and QEMU, for example, does exactly that). To make sure eVMCS is\nmapped /vmx_set_nested_state() raises KVM_REQ_GET_NESTED_STATE_PAGES\nrequest.\n\nCommit f2c7ef3ba955 (\"KVM: nSVM: cancel KVM_REQ_GET_NESTED_STATE_PAGES\non nested vmexit\") added KVM_REQ_GET_NESTED_STATE_PAGES clearing to\nnested_vmx_vmexit() to make sure MSR permission bitmap is not switched\nwhen an immediate exit from L2 to L1 happens right after migration (caused\nby a pending event, for example). Unfortunately, in the exact same\nsituation we still need to have eVMCS mapped so\nnested_sync_vmcs12_to_shadow() reflects changes in VMCS12 to eVMCS.\n\nAs a band-aid, restore nested_get_evmcs_page() when clearing\nKVM_REQ_GET_NESTED_STATE_PAGES in nested_vmx_vmexit(). The 'fix' is far\nfrom being ideal as we can't easily propagate possible failures and even if\nwe could, this is most likely already too late to do so. The whole\n'KVM_REQ_GET_NESTED_STATE_PAGES' idea for mapping eVMCS after migration\nseems to be fragile as we diverge too much from the 'native' path when\nvmptr loading happens on vmx_set_nested_state()."}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/x86/kvm/vmx/nested.c"],"versions":[{"version":"0faceb7d6dda6f370ff1fa0464d7180f7e5cb417","lessThan":"c8bf64e3fb77cc19bad146fbe26651985b117194","status":"affected","versionType":"git"},{"version":"f2c7ef3ba9556d62a7e2bb23b563c6510007d55c","lessThan":"200a45649ab7361bc80c70aebf7165b64f9a6c9f","status":"affected","versionType":"git"},{"version":"f2c7ef3ba9556d62a7e2bb23b563c6510007d55c","lessThan":"bd0e8455b85b651a4c77de9616e307129b15aaa7","status":"affected","versionType":"git"},{"version":"f2c7ef3ba9556d62a7e2bb23b563c6510007d55c","lessThan":"f5c7e8425f18fdb9bdb7d13340651d7876890329","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/vmx/nested.c"],"versions":[{"version":"5.11","status":"affected"},{"version":"0","lessThan":"5.11","status":"unaffected","versionType":"semver"},{"version":"5.10.38","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.11.22","lessThanOrEqual":"5.11.*","status":"unaffected","versionType":"semver"},{"version":"5.12.5","lessThanOrEqual":"5.12.*","status":"unaffected","versionType":"semver"},{"version":"5.13","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":"5.10.13","versionEndExcluding":"5.10.38"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"5.11.22"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"5.12.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"5.13"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/c8bf64e3fb77cc19bad146fbe26651985b117194"},{"url":"https://git.kernel.org/stable/c/200a45649ab7361bc80c70aebf7165b64f9a6c9f"},{"url":"https://git.kernel.org/stable/c/bd0e8455b85b651a4c77de9616e307129b15aaa7"},{"url":"https://git.kernel.org/stable/c/f5c7e8425f18fdb9bdb7d13340651d7876890329"}],"title":"KVM: nVMX: Always make an attempt to map eVMCS after migration","x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"problemTypes":[{"descriptions":[{"type":"CWE","lang":"en","description":"CWE-noinfo Not enough information"}]}],"affected":[{"vendor":"linux","product":"linux_kernel","cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"],"defaultStatus":"unknown","versions":[{"version":"0faceb7d6dda","status":"affected","lessThan":"c8bf64e3fb77","versionType":"git"},{"version":"f2c7ef3ba955","status":"affected","lessThan":"200a45649ab7","versionType":"git"},{"version":"f2c7ef3ba955","status":"affected","lessThan":"bd0e8455b85b","versionType":"git"},{"version":"f2c7ef3ba955","status":"affected","lessThan":"f5c7e8425f18","versionType":"git"},{"version":"5.11","status":"affected"},{"version":"0","status":"affected","lessThan":"5.11*","versionType":"semver"},{"version":"5.10.38","status":"affected","lessThanOrEqual":"5.11*","versionType":"semver"},{"version":"5.12.5","status":"affected","lessThanOrEqual":"5.12*","versionType":"semver"},{"version":"5.13","status":"affected","lessThanOrEqual":"*","versionType":"semver"}]}],"metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":7.8,"attackVector":"LOCAL","baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","integrityImpact":"HIGH","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"HIGH","privilegesRequired":"LOW","confidentialityImpact":"HIGH"}},{"other":{"type":"ssvc","content":{"timestamp":"2024-11-04T17:39:28.108559Z","id":"CVE-2021-46978","options":[{"Exploitation":"none"},{"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":"2024-11-04T17:46:50.654Z"}},{"providerMetadata":{"orgId":"af854a3a-2127-422b-91ae-364da2661108","shortName":"CVE","dateUpdated":"2024-08-04T05:24:37.902Z"},"title":"CVE Program Container","references":[{"url":"https://git.kernel.org/stable/c/c8bf64e3fb77cc19bad146fbe26651985b117194","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/200a45649ab7361bc80c70aebf7165b64f9a6c9f","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/bd0e8455b85b651a4c77de9616e307129b15aaa7","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/f5c7e8425f18fdb9bdb7d13340651d7876890329","tags":["x_transferred"]}]}]}}