FKIE_CVE-2021-47062

Vulnerability from fkie_nvd - Published: 2024-02-29 23:15 - Updated: 2026-06-17 04:16
Severity
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: KVM: SVM: Use online_vcpus, not created_vcpus, to iterate over vCPUs Use the kvm_for_each_vcpu() helper to iterate over vCPUs when encrypting VMSAs for SEV, which effectively switches to use online_vcpus instead of created_vcpus. This fixes a possible null-pointer dereference as created_vcpus does not guarantee a vCPU exists, since it is updated at the very beginning of KVM_CREATE_VCPU. created_vcpus exists to allow the bulk of vCPU creation to run in parallel, while still correctly restricting the max number of max vCPUs.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ba7bf5d6336aa9c0d977b161bfa420c56d46ee40Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/bd0cced2ae93195668f983d443f7f17e8efd24d2Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c36b16d29f3af5f32fc1b2a3401bf48f71cabee1Patch
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/stable/c/ba7bf5d6336aa9c0d977b161bfa420c56d46ee40Patch
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/stable/c/bd0cced2ae93195668f983d443f7f17e8efd24d2Patch
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/stable/c/c36b16d29f3af5f32fc1b2a3401bf48f71cabee1Patch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/kvm/svm/sev.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "bd0cced2ae93195668f983d443f7f17e8efd24d2",
              "status": "affected",
              "version": "ad73109ae7ec30d5bfb76be108e304f9f0af4829",
              "versionType": "git"
            },
            {
              "lessThan": "ba7bf5d6336aa9c0d977b161bfa420c56d46ee40",
              "status": "affected",
              "version": "ad73109ae7ec30d5bfb76be108e304f9f0af4829",
              "versionType": "git"
            },
            {
              "lessThan": "c36b16d29f3af5f32fc1b2a3401bf48f71cabee1",
              "status": "affected",
              "version": "ad73109ae7ec30d5bfb76be108e304f9f0af4829",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/kvm/svm/sev.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.11"
            },
            {
              "lessThan": "5.11",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.11.*",
              "status": "unaffected",
              "version": "5.11.21",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.12.*",
              "status": "unaffected",
              "version": "5.12.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "5.13",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "8CBB94EC-EC33-4464-99C5-03E5542715F0",
              "versionEndExcluding": "5.11.21",
              "versionStartIncluding": "5.11",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "D8C7052F-1B7B-4327-9C2B-84EBF3243838",
              "versionEndExcluding": "5.12.4",
              "versionStartIncluding": "5.12",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: SVM: Use online_vcpus, not created_vcpus, to iterate over vCPUs\n\nUse the kvm_for_each_vcpu() helper to iterate over vCPUs when encrypting\nVMSAs for SEV, which effectively switches to use online_vcpus instead of\ncreated_vcpus.  This fixes a possible null-pointer dereference as\ncreated_vcpus does not guarantee a vCPU exists, since it is updated at\nthe very beginning of KVM_CREATE_VCPU.  created_vcpus exists to allow the\nbulk of vCPU creation to run in parallel, while still correctly\nrestricting the max number of max vCPUs."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: KVM: SVM: use online_vcpus, no creado_vcpus, para iterar sobre vCPU. Use el asistente kvm_for_each_vcpu() para iterar sobre vCPU al cifrar VMSA para SEV, que efectivamente cambia para usar online_vcpus en lugar de creado_vcpus. Esto corrige una posible desreferencia de puntero nulo ya que create_vcpus no garantiza que exista una vCPU, ya que se actualiza al comienzo de KVM_CREATE_VCPU. create_vcpus existe para permitir que la mayor parte de la creaci\u00f3n de vCPU se ejecute en paralelo, al mismo tiempo que restringe correctamente la cantidad m\u00e1xima de vCPU m\u00e1ximas."
    }
  ],
  "id": "CVE-2021-47062",
  "lastModified": "2026-06-17T04:16:21.307",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 3.6,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2021-47062",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2024-03-05T22:14:24.335971Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2024-02-29T23:15:07.843",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/ba7bf5d6336aa9c0d977b161bfa420c56d46ee40"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/bd0cced2ae93195668f983d443f7f17e8efd24d2"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/c36b16d29f3af5f32fc1b2a3401bf48f71cabee1"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/ba7bf5d6336aa9c0d977b161bfa420c56d46ee40"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/bd0cced2ae93195668f983d443f7f17e8efd24d2"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/c36b16d29f3af5f32fc1b2a3401bf48f71cabee1"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-476"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}


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