FKIE_CVE-2021-47008

Vulnerability from fkie_nvd - Published: 2024-02-28 09:15 - 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: Make sure GHCB is mapped before updating Access to the GHCB is mainly in the VMGEXIT path and it is known that the GHCB will be mapped. But there are two paths where it is possible the GHCB might not be mapped. The sev_vcpu_deliver_sipi_vector() routine will update the GHCB to inform the caller of the AP Reset Hold NAE event that a SIPI has been delivered. However, if a SIPI is performed without a corresponding AP Reset Hold, then the GHCB might not be mapped (depending on the previous VMEXIT), which will result in a NULL pointer dereference. The svm_complete_emulated_msr() routine will update the GHCB to inform the caller of a RDMSR/WRMSR operation about any errors. While it is likely that the GHCB will be mapped in this situation, add a safe guard in this path to be certain a NULL pointer dereference is not encountered.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a3ba26ecfb569f4aa3f867e80c02aa65f20aadadPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/fb9e14f4f8217a0980f8da2c8ff70dee058cbe47Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/fd722a57fe0b80133dacae4e1c852ee4212f9b2ePatch
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/stable/c/a3ba26ecfb569f4aa3f867e80c02aa65f20aadadPatch
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/stable/c/fb9e14f4f8217a0980f8da2c8ff70dee058cbe47Patch
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/stable/c/fd722a57fe0b80133dacae4e1c852ee4212f9b2ePatch
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",
            "arch/x86/kvm/svm/svm.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "fb9e14f4f8217a0980f8da2c8ff70dee058cbe47",
              "status": "affected",
              "version": "f1c6366e304328de301be362eca905a3503ff33b",
              "versionType": "git"
            },
            {
              "lessThan": "fd722a57fe0b80133dacae4e1c852ee4212f9b2e",
              "status": "affected",
              "version": "f1c6366e304328de301be362eca905a3503ff33b",
              "versionType": "git"
            },
            {
              "lessThan": "a3ba26ecfb569f4aa3f867e80c02aa65f20aadad",
              "status": "affected",
              "version": "f1c6366e304328de301be362eca905a3503ff33b",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/kvm/svm/sev.c",
            "arch/x86/kvm/svm/svm.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": "5.11.22",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.12.*",
              "status": "unaffected",
              "version": "5.12.5",
              "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": "83B53E9A-F426-4C03-9A5F-A931FF79827E",
              "versionEndExcluding": "5.11.22",
              "versionStartIncluding": "5.11",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "0274929A-B36C-4F4C-AB22-30A0DD6B995B",
              "versionEndExcluding": "5.12.5",
              "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: Make sure GHCB is mapped before updating\n\nAccess to the GHCB is mainly in the VMGEXIT path and it is known that the\nGHCB will be mapped. But there are two paths where it is possible the GHCB\nmight not be mapped.\n\nThe sev_vcpu_deliver_sipi_vector() routine will update the GHCB to inform\nthe caller of the AP Reset Hold NAE event that a SIPI has been delivered.\nHowever, if a SIPI is performed without a corresponding AP Reset Hold,\nthen the GHCB might not be mapped (depending on the previous VMEXIT),\nwhich will result in a NULL pointer dereference.\n\nThe svm_complete_emulated_msr() routine will update the GHCB to inform\nthe caller of a RDMSR/WRMSR operation about any errors. While it is likely\nthat the GHCB will be mapped in this situation, add a safe guard\nin this path to be certain a NULL pointer dereference is not encountered."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: KVM: SVM: aseg\u00farese de que GHCB est\u00e9 mapeado antes de actualizar. El acceso al GHCB se encuentra principalmente en la ruta VMGEXIT y se sabe que el GHCB ser\u00e1 mapeado. Pero hay dos caminos en los que es posible que el GHCB no est\u00e9 mapeado. La rutina sev_vcpu_deliver_sipi_vector() actualizar\u00e1 el GHCB para informar a la persona que llama del evento AP Reset Hold NAE que se ha entregado un SIPI. Sin embargo, si se realiza una SIPI sin una retenci\u00f3n de reinicio de AP correspondiente, es posible que el GHCB no se asigne (dependiendo del VMEXIT anterior), lo que resultar\u00e1 en una desreferencia del puntero NULL. La rutina svm_complete_emulated_msr() actualizar\u00e1 el GHCB para informar a la persona que llama de una operaci\u00f3n RDMSR/WRMSR sobre cualquier error. Si bien es probable que el GHCB se asigne en esta situaci\u00f3n, agregue una protecci\u00f3n en esta ruta para asegurarse de que no se encuentre una desreferencia de puntero NULL."
    }
  ],
  "id": "CVE-2021-47008",
  "lastModified": "2026-06-17T04:16:09.973",
  "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-2021-47008",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2024-09-10T15:58:15.859312Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2024-02-28T09:15:38.560",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/a3ba26ecfb569f4aa3f867e80c02aa65f20aadad"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/fb9e14f4f8217a0980f8da2c8ff70dee058cbe47"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/fd722a57fe0b80133dacae4e1c852ee4212f9b2e"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/a3ba26ecfb569f4aa3f867e80c02aa65f20aadad"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/fb9e14f4f8217a0980f8da2c8ff70dee058cbe47"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/fd722a57fe0b80133dacae4e1c852ee4212f9b2e"
    }
  ],
  "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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