{
  "schemaVersion": 1,
  "attribution": [
    {
      "source": "CISA Known Exploited Vulnerabilities",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "licence": "US government work"
    },
    {
      "source": "GitHub Advisory Database",
      "url": "https://github.com/advisories",
      "licence": "CC BY 4.0"
    },
    {
      "source": "Have I Been Pwned",
      "url": "https://haveibeenpwned.com/",
      "licence": "CC BY 4.0"
    },
    {
      "source": "CVE Program (CVE records)",
      "url": "https://www.cve.org/Legal/TermsOfUse",
      "licence": "CVE Terms of Use",
      "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.",
      "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss/",
      "licence": "free to use; FIRST requests attribution"
    }
  ],
  "record": {
    "id": "CVE-2021-46978",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2021-46978",
    "idYear": 2021,
    "status": "PUBLISHED",
    "publishedAt": "2024-02-28T08:13:09.106Z",
    "updatedAt": "2026-05-23T15:18:50.711Z",
    "importedAt": "2026-10-24T01:56:36.661Z",
    "snapshot": {
      "id": "cve_2026-10-24_midnight_baseline",
      "at": "2026-10-24T00:00:00.000Z",
      "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z"
    },
    "facts": {
      "title": "KVM: nVMX: Always make an attempt to map eVMCS after migration",
      "summary": "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": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "0faceb7d6dda6f370ff1fa0464d7180f7e5cb417",
              "status": "affected",
              "versionType": "git",
              "lessThan": "c8bf64e3fb77cc19bad146fbe26651985b117194"
            },
            {
              "version": "f2c7ef3ba9556d62a7e2bb23b563c6510007d55c",
              "status": "affected",
              "versionType": "git",
              "lessThan": "200a45649ab7361bc80c70aebf7165b64f9a6c9f"
            },
            {
              "version": "f2c7ef3ba9556d62a7e2bb23b563c6510007d55c",
              "status": "affected",
              "versionType": "git",
              "lessThan": "bd0e8455b85b651a4c77de9616e307129b15aaa7"
            },
            {
              "version": "f2c7ef3ba9556d62a7e2bb23b563c6510007d55c",
              "status": "affected",
              "versionType": "git",
              "lessThan": "f5c7e8425f18fdb9bdb7d13340651d7876890329"
            },
            {
              "version": "5.10.13",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "5.10.38"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "versions": [
            {
              "version": "5.11",
              "status": "affected"
            },
            {
              "version": "0",
              "status": "unaffected",
              "versionType": "semver",
              "lessThan": "5.11"
            },
            {
              "version": "5.10.38",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "version": "5.11.22",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "5.11.*"
            },
            {
              "version": "5.12.5",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "5.12.*"
            },
            {
              "version": "5.13",
              "status": "unaffected",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ]
        }
      ]
    }
  }
}