FKIE_CVE-2021-43540

Vulnerability from fkie_nvd - Published: 2021-12-08 22:15 - Updated: 2026-06-17 04:11
Severity
6.5 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
Summary
WebExtensions with the correct permissions were able to create and install ServiceWorkers for third-party websites that would not have been uninstalled with the extension. This vulnerability affects Firefox < 95.
References
security@mozilla.orghttps://bugzilla.mozilla.org/show_bug.cgi?id=1636629Issue Tracking, Permissions Required, Vendor Advisory
security@mozilla.orghttps://security.gentoo.org/glsa/202202-03Third Party Advisory
security@mozilla.orghttps://www.mozilla.org/security/advisories/mfsa2021-52/Vendor Advisory
af854a3a-2127-422b-91ae-364da2661108https://bugzilla.mozilla.org/show_bug.cgi?id=1636629Issue Tracking, Permissions Required, Vendor Advisory
af854a3a-2127-422b-91ae-364da2661108https://security.gentoo.org/glsa/202202-03Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://www.mozilla.org/security/advisories/mfsa2021-52/Vendor Advisory
Impacted products
Vendor Product Version
mozilla firefox *
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "Firefox",
          "vendor": "Mozilla",
          "versions": [
            {
              "lessThan": "95",
              "status": "affected",
              "version": "unspecified",
              "versionType": "custom"
            }
          ]
        }
      ],
      "source": "security@mozilla.org"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "83D69E34-EB94-49ED-9FA1-F68400971726",
              "versionEndExcluding": "95.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "WebExtensions with the correct permissions were able to create and install ServiceWorkers for third-party websites that would not have been uninstalled with the extension. This vulnerability affects Firefox \u003c 95."
    },
    {
      "lang": "es",
      "value": "Las WebExtensions con los permisos correctos pod\u00edan crear e instalar ServiceWorkers para sitios web de terceros que no habr\u00edan desinstalado con la extensi\u00f3n. Esta vulnerabilidad afecta a Firefox versiones anteriores a 95"
    }
  ],
  "id": "CVE-2021-43540",
  "lastModified": "2026-06-17T04:11:05.853",
  "metrics": {
    "cvssMetricV2": [
      {
        "acInsufInfo": false,
        "baseSeverity": "MEDIUM",
        "cvssData": {
          "accessComplexity": "MEDIUM",
          "accessVector": "NETWORK",
          "authentication": "NONE",
          "availabilityImpact": "NONE",
          "baseScore": 4.3,
          "confidentialityImpact": "NONE",
          "integrityImpact": "PARTIAL",
          "vectorString": "AV:N/AC:M/Au:N/C:N/I:P/A:N",
          "version": "2.0"
        },
        "exploitabilityScore": 8.6,
        "impactScore": 2.9,
        "obtainAllPrivilege": false,
        "obtainOtherPrivilege": false,
        "obtainUserPrivilege": false,
        "source": "nvd@nist.gov",
        "type": "Primary",
        "userInteractionRequired": true
      }
    ],
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 6.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 3.6,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2021-12-08T22:15:09.787",
  "references": [
    {
      "source": "security@mozilla.org",
      "tags": [
        "Issue Tracking",
        "Permissions Required",
        "Vendor Advisory"
      ],
      "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1636629"
    },
    {
      "source": "security@mozilla.org",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://security.gentoo.org/glsa/202202-03"
    },
    {
      "source": "security@mozilla.org",
      "tags": [
        "Vendor Advisory"
      ],
      "url": "https://www.mozilla.org/security/advisories/mfsa2021-52/"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Issue Tracking",
        "Permissions Required",
        "Vendor Advisory"
      ],
      "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1636629"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://security.gentoo.org/glsa/202202-03"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Vendor Advisory"
      ],
      "url": "https://www.mozilla.org/security/advisories/mfsa2021-52/"
    }
  ],
  "sourceIdentifier": "security@mozilla.org",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-noinfo"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.