CVE-2021-43540 (GCVE-0-2021-43540)

Vulnerability from cvelistv5 – Published: 2021-12-08 21:20 – Updated: 2024-08-04 04:03
VLAI
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.
Severity
6.5 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
CWE
  • WebExtensions could have installed persistent ServiceWorkers
Assigner
References
Impacted products
Vendor Product Version CPE status
Mozilla Firefox Affected: unspecified , < 95 (custom)
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-04T04:03:06.919Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "https://www.mozilla.org/security/advisories/mfsa2021-52/"
          },
          {
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1636629"
          },
          {
            "name": "GLSA-202202-03",
            "tags": [
              "vendor-advisory",
              "x_refsource_GENTOO",
              "x_transferred"
            ],
            "url": "https://security.gentoo.org/glsa/202202-03"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "Firefox",
          "vendor": "Mozilla",
          "versions": [
            {
              "lessThan": "95",
              "status": "affected",
              "version": "unspecified",
              "versionType": "custom"
            }
          ]
        }
      ],
      "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."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "description": "WebExtensions could have installed persistent ServiceWorkers",
              "lang": "en",
              "type": "text"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2022-02-22T00:06:15.000Z",
        "orgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe",
        "shortName": "mozilla"
      },
      "references": [
        {
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://www.mozilla.org/security/advisories/mfsa2021-52/"
        },
        {
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1636629"
        },
        {
          "name": "GLSA-202202-03",
          "tags": [
            "vendor-advisory",
            "x_refsource_GENTOO"
          ],
          "url": "https://security.gentoo.org/glsa/202202-03"
        }
      ],
      "x_legacyV4Record": {
        "CVE_data_meta": {
          "ASSIGNER": "security@mozilla.org",
          "ID": "CVE-2021-43540",
          "STATE": "PUBLIC"
        },
        "affects": {
          "vendor": {
            "vendor_data": [
              {
                "product": {
                  "product_data": [
                    {
                      "product_name": "Firefox",
                      "version": {
                        "version_data": [
                          {
                            "version_affected": "\u003c",
                            "version_value": "95"
                          }
                        ]
                      }
                    }
                  ]
                },
                "vendor_name": "Mozilla"
              }
            ]
          }
        },
        "data_format": "MITRE",
        "data_type": "CVE",
        "data_version": "4.0",
        "description": {
          "description_data": [
            {
              "lang": "eng",
              "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."
            }
          ]
        },
        "problemtype": {
          "problemtype_data": [
            {
              "description": [
                {
                  "lang": "eng",
                  "value": "WebExtensions could have installed persistent ServiceWorkers"
                }
              ]
            }
          ]
        },
        "references": {
          "reference_data": [
            {
              "name": "https://www.mozilla.org/security/advisories/mfsa2021-52/",
              "refsource": "MISC",
              "url": "https://www.mozilla.org/security/advisories/mfsa2021-52/"
            },
            {
              "name": "https://bugzilla.mozilla.org/show_bug.cgi?id=1636629",
              "refsource": "MISC",
              "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1636629"
            },
            {
              "name": "GLSA-202202-03",
              "refsource": "GENTOO",
              "url": "https://security.gentoo.org/glsa/202202-03"
            }
          ]
        }
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe",
    "assignerShortName": "mozilla",
    "cveId": "CVE-2021-43540",
    "datePublished": "2021-12-08T21:20:08.000Z",
    "dateReserved": "2021-11-08T00:00:00.000Z",
    "dateUpdated": "2024-08-04T04:03:06.919Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2021-43540",
      "date": "2026-09-20",
      "epss": "0.00862",
      "percentile": "0.56989"
    },
    "fkie_nvd": {
      "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"
            }
          ]
        }
      ],
      "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": "2024-11-21T06:29:23.320",
      "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"
        }
      ]
    },
    "nvd": {
      "cve": {
        "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"
          }
        ]
      }
    },
    "redhat_vex": {
      "current_release_date": "2026-03-27T13:22:44+00:00",
      "cve": "CVE-2021-43540",
      "id": "CVE-2021-43540",
      "initial_release_date": "2021-01-01T00:00:00+00:00",
      "product_status:known_not_affected": "1",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "CVE-2021-43540",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-43540.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2026-06-06T06:11:29Z",
      "cve": "CVE-2021-43540",
      "id": "CVE-2021-43540",
      "initial_release_date": "2023-02-15T03:36:54Z",
      "product_status:known_affected": "1",
      "product_status:recommended": "9",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2021-43540",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2021-43540.json",
      "version": "15"
    }
  }
}



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.


Detection rules are retrieved from Rulezet.


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.