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CVE-2020-15666

Status: ModifiedMedium (6.5)—

When trying to load a non-video in an audio/video context the exact status code (200, 302, 404, 500, 412, 403, etc.) was disclosed via the MediaError Message. This level of information leakage is inconsistent with the standardized onerror/onsuccess disclosure and can lead to inferring login status to services or device discovery on a local network among other attacks. This vulnerability affects Firefox < 80 and Firefox for Android < 80.

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 (2)

Mozilla — FirefoxMozilla — Firefox Mobile

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2020-15666",
  "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": 6.5,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/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": 2.8
      }
    ]
  },
  "affected": [
    {
      "source": "security@mozilla.org",
      "affectedData": [
        {
          "vendor": "Mozilla",
          "product": "Firefox",
          "versions": [
            {
              "status": "affected",
              "version": "unspecified",
              "lessThan": "80",
              "versionType": "custom"
            }
          ]
        },
        {
          "vendor": "Mozilla",
          "product": "Firefox for Android",
          "versions": [
            {
              "status": "affected",
              "version": "unspecified",
              "lessThan": "80",
              "versionType": "custom"
            }
          ]
        }
      ]
    }
  ],
  "published": "2020-10-01T19:15:13.203",
  "references": [
    {
      "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1450853",
      "tags": [
        "Exploit",
        "Issue Tracking",
        "Vendor Advisory"
      ],
      "source": "security@mozilla.org"
    },
    {
      "url": "https://www.mozilla.org/security/advisories/mfsa2020-36/",
      "tags": [
        "Release Notes",
        "Vendor Advisory"
      ],
      "source": "security@mozilla.org"
    },
    {
      "url": "https://www.mozilla.org/security/advisories/mfsa2020-39/",
      "tags": [
        "Release Notes",
        "Vendor Advisory"
      ],
      "source": "security@mozilla.org"
    },
    {
      "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1450853",
      "tags": [
        "Exploit",
        "Issue Tracking",
        "Vendor Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://www.mozilla.org/security/advisories/mfsa2020-36/",
      "tags": [
        "Release Notes",
        "Vendor Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://www.mozilla.org/security/advisories/mfsa2020-39/",
      "tags": [
        "Release Notes",
        "Vendor Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-209"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "When trying to load a non-video in an audio/video context the exact status code (200, 302, 404, 500, 412, 403, etc.) was disclosed via the MediaError Message. This level of information leakage is inconsistent with the standardized onerror/onsuccess disclosure and can lead to inferring login status to services or device discovery on a local network among other attacks. This vulnerability affects Firefox < 80 and Firefox for Android < 80."
    },
    {
      "lang": "es",
      "value": "Cuando se intenta cargar un archivo que no es de video en un contexto de audio y video, el código de estado exacto (200, 302, 404, 500, 412, 403, etc.) fue revelado por medio del MediaError Message.&#xa0;Este nivel de filtración de información es inconsistente con la divulgación estandarizada onerror/onsuccess y puede conllevar a inferir el estado de inicio de sesión a los servicios o a la detección de dispositivos en una red local, entre otros ataques.&#xa0;Esta vulnerabilidad afecta a Firefox versiones anteriores a 80 y Firefox para Android versiones anteriores a 80"
    }
  ],
  "lastModified": "2026-08-19T15:29:21.807",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:mozilla:firefox:*:*:*:*:*:-:*:*",
              "vulnerable": true,
              "matchCriteriaId": "02FEC5B0-7705-414F-B2F7-BB6F82C1C04F",
              "versionEndExcluding": "80.0"
            },
            {
              "criteria": "cpe:2.3:a:mozilla:firefox_mobile:*:*:*:*:*:android:*:*",
              "vulnerable": true,
              "matchCriteriaId": "4C4125BF-EDD0-4416-89ED-63635CA0BDD7",
              "versionEndExcluding": "80.0"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "security@mozilla.org"
}