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CVE-2021-30817

Status: ModifiedMedium (5.5)—

A permissions issue was addressed with improved validation. This issue is fixed in macOS Big Sur 11.5. A malicious application may be able to access data about the accounts the user is using Family Sharing with.

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Affected technologies (1)

Apple — Macos

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2021-30817",
  "cveTags": [],
  "metrics": {
    "cvssMetricV2": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 4.3,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:M/Au:N/C:P/I:N/A:N",
          "authentication": "NONE",
          "integrityImpact": "NONE",
          "accessComplexity": "MEDIUM",
          "availabilityImpact": "NONE",
          "confidentialityImpact": "PARTIAL"
        },
        "acInsufInfo": false,
        "impactScore": 2.9,
        "baseSeverity": "MEDIUM",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 8.6,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": true
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 5.5,
          "attackVector": "LOCAL",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N",
          "integrityImpact": "NONE",
          "userInteraction": "REQUIRED",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "affected": [
    {
      "source": "product-security@apple.com",
      "affectedData": [
        {
          "vendor": "Apple",
          "product": "macOS",
          "versions": [
            {
              "status": "affected",
              "version": "unspecified",
              "lessThan": "11.5",
              "versionType": "custom"
            }
          ]
        }
      ]
    }
  ],
  "published": "2021-10-28T19:15:08.947",
  "references": [
    {
      "url": "https://support.apple.com/en-us/HT212602",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "product-security@apple.com"
    },
    {
      "url": "https://support.apple.com/en-us/HT212602",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-noinfo"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "A permissions issue was addressed with improved validation. This issue is fixed in macOS Big Sur 11.5. A malicious application may be able to access data about the accounts the user is using Family Sharing with."
    },
    {
      "lang": "es",
      "value": "Se abordó un problema de permisos con una comprobación mejorada. Este problema se corrigió en macOS Big Sur versión 11.5. Una aplicación maliciosa podría acceder a los datos de las cuentas con las que el usuario usa Compartir en Familia"
    }
  ],
  "lastModified": "2026-06-17T03:50:56.767",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:apple:macos:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "91CD5E8A-20E3-4193-BD1F-99FB1147081C",
              "versionEndExcluding": "11.5"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "product-security@apple.com"
}