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CVE-2016-2820

Status: ModifiedMedium (4.3)—

The Firefox Health Reports (aka FHR or about:healthreport) feature in Mozilla Firefox before 46.0 does not properly restrict the origin of events, which makes it easier for remote attackers to modify sharing preferences by leveraging access to the remote-report IFRAME element.

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)

Mozilla — Firefox

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2016-2820",
  "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:N/I:P/A:N",
          "authentication": "NONE",
          "integrityImpact": "PARTIAL",
          "accessComplexity": "MEDIUM",
          "availabilityImpact": "NONE",
          "confidentialityImpact": "NONE"
        },
        "acInsufInfo": false,
        "impactScore": 2.9,
        "baseSeverity": "MEDIUM",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 8.6,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": true
      }
    ],
    "cvssMetricV30": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.0",
          "baseScore": 4.3,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N",
          "integrityImpact": "LOW",
          "userInteraction": "REQUIRED",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 1.4,
        "exploitabilityScore": 2.8
      }
    ]
  },
  "affected": [
    {
      "source": "security@mozilla.org",
      "affectedData": [
        {
          "vendor": "n/a",
          "product": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ]
    }
  ],
  "published": "2016-04-30T17:59:15.773",
  "references": [
    {
      "url": "http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00005.html",
      "source": "security@mozilla.org"
    },
    {
      "url": "http://lists.opensuse.org/opensuse-updates/2016-05/msg00038.html",
      "source": "security@mozilla.org"
    },
    {
      "url": "http://www.mozilla.org/security/announce/2016/mfsa2016-48.html",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "security@mozilla.org"
    },
    {
      "url": "http://www.securitytracker.com/id/1035692",
      "source": "security@mozilla.org"
    },
    {
      "url": "http://www.ubuntu.com/usn/USN-2936-1",
      "source": "security@mozilla.org"
    },
    {
      "url": "http://www.ubuntu.com/usn/USN-2936-2",
      "source": "security@mozilla.org"
    },
    {
      "url": "http://www.ubuntu.com/usn/USN-2936-3",
      "source": "security@mozilla.org"
    },
    {
      "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=870870",
      "source": "security@mozilla.org"
    },
    {
      "url": "https://security.gentoo.org/glsa/201701-15",
      "source": "security@mozilla.org"
    },
    {
      "url": "http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00005.html",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://lists.opensuse.org/opensuse-updates/2016-05/msg00038.html",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://www.mozilla.org/security/announce/2016/mfsa2016-48.html",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://www.securitytracker.com/id/1035692",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://www.ubuntu.com/usn/USN-2936-1",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://www.ubuntu.com/usn/USN-2936-2",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://www.ubuntu.com/usn/USN-2936-3",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=870870",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://security.gentoo.org/glsa/201701-15",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-284"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "The Firefox Health Reports (aka FHR or about:healthreport) feature in Mozilla Firefox before 46.0 does not properly restrict the origin of events, which makes it easier for remote attackers to modify sharing preferences by leveraging access to the remote-report IFRAME element."
    },
    {
      "lang": "es",
      "value": "La funcionalidad Firefox Health Reports (también conocida como FHR o about:healthreport) en Mozilla Firefox en versiones anteriores a 46.0 no restringe adecuadamente el origen de eventos, lo que facilita a atacantes remotos modificar preferencias de compartición aprovechando acceso al elemento IFRAME remote-report."
    }
  ],
  "lastModified": "2026-06-17T00:44:31.513",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "97000851-C511-487E-A5E8-FCB173D76624",
              "versionEndIncluding": "45.0.2"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "security@mozilla.org"
}