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CVE-2016-4745

Status: ModifiedMedium (5.3)—

The Kerberos 5 (aka krb5) PAM module in Apple OS X before 10.12 does not use constant-time operations for determining username validity, which makes it easier for remote attackers to enumerate user accounts via a timing side-channel attack.

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 — MAC OS X

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2016-4745",
  "cveTags": [],
  "metrics": {
    "cvssMetricV2": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 5,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:L/Au:N/C:P/I:N/A:N",
          "authentication": "NONE",
          "integrityImpact": "NONE",
          "accessComplexity": "LOW",
          "availabilityImpact": "NONE",
          "confidentialityImpact": "PARTIAL"
        },
        "acInsufInfo": false,
        "impactScore": 2.9,
        "baseSeverity": "MEDIUM",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 10,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": false
      }
    ],
    "cvssMetricV30": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.0",
          "baseScore": 5.3,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "LOW"
        },
        "impactScore": 1.4,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "product-security@apple.com",
      "affectedData": [
        {
          "vendor": "n/a",
          "product": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ]
    }
  ],
  "published": "2016-09-25T10:59:44.987",
  "references": [
    {
      "url": "http://lists.apple.com/archives/security-announce/2016/Sep/msg00006.html",
      "tags": [
        "Mailing List",
        "Vendor Advisory"
      ],
      "source": "product-security@apple.com"
    },
    {
      "url": "http://www.securityfocus.com/bid/93055",
      "source": "product-security@apple.com"
    },
    {
      "url": "http://www.securitytracker.com/id/1036858",
      "source": "product-security@apple.com"
    },
    {
      "url": "https://support.apple.com/HT207170",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "product-security@apple.com"
    },
    {
      "url": "http://lists.apple.com/archives/security-announce/2016/Sep/msg00006.html",
      "tags": [
        "Mailing List",
        "Vendor Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://www.securityfocus.com/bid/93055",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://www.securitytracker.com/id/1036858",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://support.apple.com/HT207170",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-200"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "The Kerberos 5 (aka krb5) PAM module in Apple OS X before 10.12 does not use constant-time operations for determining username validity, which makes it easier for remote attackers to enumerate user accounts via a timing side-channel attack."
    },
    {
      "lang": "es",
      "value": "El módulo PAM de Kerberos 5 (también conocido como krb5) en Apple OS X en versiones anteriores a 10.12 no utiliza operaciones de tiempo constante para determinar la validación de nombre de usuario, lo que facilita a atacantes remotos enumerar cuentas de usuario a través de un ataque de sincronización de canal lateral."
    }
  ],
  "lastModified": "2026-06-17T00:48:08.623",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:apple:mac_os_x:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "FEEAF544-405E-4A75-9206-5CC4EDCE2F05",
              "versionEndIncluding": "10.11.6"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "product-security@apple.com"
}