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CVE-2021-24000

Status: ModifiedLow (3.1)—

A race condition with requestPointerLock() and setTimeout() could have resulted in a user interacting with one tab when they believed they were on a separate tab. In conjunction with certain elements (such as &lt;input type="file"&gt;) this could have led to an attack where a user was confused about the origin of the webpage and potentially disclosed information they did not intend to. This vulnerability affects Firefox < 88.

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-2021-24000",
  "cveTags": [],
  "metrics": {
    "cvssMetricV2": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 2.6,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:H/Au:N/C:P/I:N/A:N",
          "authentication": "NONE",
          "integrityImpact": "NONE",
          "accessComplexity": "HIGH",
          "availabilityImpact": "NONE",
          "confidentialityImpact": "PARTIAL"
        },
        "acInsufInfo": false,
        "impactScore": 2.9,
        "baseSeverity": "LOW",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 4.9,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": true
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 3.1,
          "attackVector": "NETWORK",
          "baseSeverity": "LOW",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N",
          "integrityImpact": "NONE",
          "userInteraction": "REQUIRED",
          "attackComplexity": "HIGH",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "LOW"
        },
        "impactScore": 1.4,
        "exploitabilityScore": 1.6
      }
    ]
  },
  "affected": [
    {
      "source": "security@mozilla.org",
      "affectedData": [
        {
          "vendor": "Mozilla",
          "product": "Firefox",
          "versions": [
            {
              "status": "affected",
              "version": "unspecified",
              "lessThan": "88",
              "versionType": "custom"
            }
          ]
        }
      ]
    }
  ],
  "published": "2021-06-24T14:15:09.513",
  "references": [
    {
      "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1694698",
      "tags": [
        "Issue Tracking",
        "Permissions Required",
        "Vendor Advisory"
      ],
      "source": "security@mozilla.org"
    },
    {
      "url": "https://www.mozilla.org/security/advisories/mfsa2021-16/",
      "tags": [
        "Release Notes",
        "Vendor Advisory"
      ],
      "source": "security@mozilla.org"
    },
    {
      "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1694698",
      "tags": [
        "Issue Tracking",
        "Permissions Required",
        "Vendor Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://www.mozilla.org/security/advisories/mfsa2021-16/",
      "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-362"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "A race condition with requestPointerLock() and setTimeout() could have resulted in a user interacting with one tab when they believed they were on a separate tab. In conjunction with certain elements (such as &lt;input type=\"file\"&gt;) this could have led to an attack where a user was confused about the origin of the webpage and potentially disclosed information they did not intend to. This vulnerability affects Firefox < 88."
    },
    {
      "lang": "es",
      "value": "Una condición de carrera con las funciones requestPointerLock() y setTimeout() podría haber resultado en un usuario interactuando con una pestaña cuando creía que estaba en una pestaña separada. En conjunción con determinados elementos (como &lt;input type=\"file\"&gt;) esto podría haber conllevado a un ataque donde un usuario se confundiera sobre el origen de la página web y potencialmente revelara información que no pretendía. Esta vulnerabilidad afecta a Firefox versiones anteriores a 88"
    }
  ],
  "lastModified": "2026-06-17T03:39:08.223",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "05F82833-4C58-4D1A-B9FC-EDBE88FF93EA",
              "versionEndExcluding": "88.0"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "security@mozilla.org"
}