Vulnerability-Lookup

FKIE_CVE-2021-23971

Vulnerability from fkie_nvd - Published: 2021-02-26 02:15 - Updated: 2026-06-17 03:39

Severity

6.5 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

Summary

When processing a redirect with a conflicting Referrer-Policy, Firefox would have adopted the redirect's Referrer-Policy. This would have potentially resulted in more information than intended by the original origin being provided to the destination of the redirect. This vulnerability affects Firefox < 86.

References

URL	Tags
security@mozilla.org	https://bugzilla.mozilla.org/show_bug.cgi?id=1678545	Issue Tracking, Permissions Required, Vendor Advisory
security@mozilla.org	https://security.gentoo.org/glsa/202104-10	Third Party Advisory
security@mozilla.org	https://www.mozilla.org/security/advisories/mfsa2021-07/	Release Notes, Vendor Advisory
af854a3a-2127-422b-91ae-364da2661108	https://bugzilla.mozilla.org/show_bug.cgi?id=1678545	Issue Tracking, Permissions Required, Vendor Advisory
af854a3a-2127-422b-91ae-364da2661108	https://security.gentoo.org/glsa/202104-10	Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108	https://www.mozilla.org/security/advisories/mfsa2021-07/	Release Notes, Vendor Advisory

Impacted products

	Vendor	Product	Version
	mozilla	firefox	*

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "Firefox",
          "vendor": "Mozilla",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 86"
            }
          ]
        }
      ],
      "source": "security@mozilla.org"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "89580DC6-183F-46F0-A27E-4E16D6B10EB6",
              "versionEndExcluding": "86.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "When processing a redirect with a conflicting Referrer-Policy, Firefox would have adopted the redirect\u0027s Referrer-Policy. This would have potentially resulted in more information than intended by the original origin being provided to the destination of the redirect. This vulnerability affects Firefox \u003c 86."
    },
    {
      "lang": "es",
      "value": "Cuando se procesa un redireccionamiento con una Pol\u00edtica de Referencia en conflicto, Firefox habr\u00eda adoptado la Pol\u00edtica de Referencia de redireccionamiento.\u0026#xa0;Esto podr\u00eda haber conllevado a que se proporcionara m\u00e1s informaci\u00f3n de la que pretend\u00eda mediante la fuente original hacia el destino del redireccionamiento.\u0026#xa0;Esta vulnerabilidad afecta a Firefox versiones anteriores a 86"
    }
  ],
  "id": "CVE-2021-23971",
  "lastModified": "2026-06-17T03:39:05.333",
  "metrics": {
    "cvssMetricV2": [
      {
        "acInsufInfo": false,
        "baseSeverity": "MEDIUM",
        "cvssData": {
          "accessComplexity": "MEDIUM",
          "accessVector": "NETWORK",
          "authentication": "NONE",
          "availabilityImpact": "NONE",
          "baseScore": 4.3,
          "confidentialityImpact": "PARTIAL",
          "integrityImpact": "NONE",
          "vectorString": "AV:N/AC:M/Au:N/C:P/I:N/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": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 3.6,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2021-02-26T02:15:13.103",
  "references": [
    {
      "source": "security@mozilla.org",
      "tags": [
        "Issue Tracking",
        "Permissions Required",
        "Vendor Advisory"
      ],
      "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1678545"
    },
    {
      "source": "security@mozilla.org",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://security.gentoo.org/glsa/202104-10"
    },
    {
      "source": "security@mozilla.org",
      "tags": [
        "Release Notes",
        "Vendor Advisory"
      ],
      "url": "https://www.mozilla.org/security/advisories/mfsa2021-07/"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Issue Tracking",
        "Permissions Required",
        "Vendor Advisory"
      ],
      "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1678545"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://security.gentoo.org/glsa/202104-10"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Release Notes",
        "Vendor Advisory"
      ],
      "url": "https://www.mozilla.org/security/advisories/mfsa2021-07/"
    }
  ],
  "sourceIdentifier": "security@mozilla.org",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-noinfo"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}

CVE-2021-23971 (GCVE-0-2021-23971)

Vulnerability from cvelistv5 – Published: 2021-02-26 01:55 – Updated: 2024-08-03 19:14

Summary

Severity

No CVSS data available.

CWE

A website's Referrer-Policy could have been be overridden, potentially resulting in the full URL being sent as a Referrer

Assigner

mozilla mitre root

References

3 references

URL	Tags
https://www.mozilla.org/security/advisories/mfsa2…	x_refsource_MISC
https://bugzilla.mozilla.org/show_bug.cgi?id=1678545	x_refsource_MISC
https://security.gentoo.org/glsa/202104-10	vendor-advisoryx_refsource_GENTOO

Impacted products

1 product

Vendor	Product	Version
Mozilla	Firefox	Affected: < 86

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-03T19:14:09.872Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "https://www.mozilla.org/security/advisories/mfsa2021-07/"
          },
          {
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1678545"
          },
          {
            "name": "GLSA-202104-10",
            "tags": [
              "vendor-advisory",
              "x_refsource_GENTOO",
              "x_transferred"
            ],
            "url": "https://security.gentoo.org/glsa/202104-10"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "Firefox",
          "vendor": "Mozilla",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 86"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "When processing a redirect with a conflicting Referrer-Policy, Firefox would have adopted the redirect\u0027s Referrer-Policy. This would have potentially resulted in more information than intended by the original origin being provided to the destination of the redirect. This vulnerability affects Firefox \u003c 86."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "description": "A website\u0027s Referrer-Policy could have been be overridden, potentially resulting in the full URL being sent as a Referrer",
              "lang": "en",
              "type": "text"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2021-05-01T01:06:43.000Z",
        "orgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe",
        "shortName": "mozilla"
      },
      "references": [
        {
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://www.mozilla.org/security/advisories/mfsa2021-07/"
        },
        {
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1678545"
        },
        {
          "name": "GLSA-202104-10",
          "tags": [
            "vendor-advisory",
            "x_refsource_GENTOO"
          ],
          "url": "https://security.gentoo.org/glsa/202104-10"
        }
      ],
      "x_legacyV4Record": {
        "CVE_data_meta": {
          "ASSIGNER": "security@mozilla.org",
          "ID": "CVE-2021-23971",
          "STATE": "PUBLIC"
        },
        "affects": {
          "vendor": {
            "vendor_data": [
              {
                "product": {
                  "product_data": [
                    {
                      "product_name": "Firefox",
                      "version": {
                        "version_data": [
                          {
                            "version_value": "\u003c 86"
                          }
                        ]
                      }
                    }
                  ]
                },
                "vendor_name": "Mozilla"
              }
            ]
          }
        },
        "data_format": "MITRE",
        "data_type": "CVE",
        "data_version": "4.0",
        "description": {
          "description_data": [
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              "lang": "eng",
              "value": "When processing a redirect with a conflicting Referrer-Policy, Firefox would have adopted the redirect\u0027s Referrer-Policy. This would have potentially resulted in more information than intended by the original origin being provided to the destination of the redirect. This vulnerability affects Firefox \u003c 86."
            }
          ]
        },
        "problemtype": {
          "problemtype_data": [
            {
              "description": [
                {
                  "lang": "eng",
                  "value": "A website\u0027s Referrer-Policy could have been be overridden, potentially resulting in the full URL being sent as a Referrer"
                }
              ]
            }
          ]
        },
        "references": {
          "reference_data": [
            {
              "name": "https://www.mozilla.org/security/advisories/mfsa2021-07/",
              "refsource": "MISC",
              "url": "https://www.mozilla.org/security/advisories/mfsa2021-07/"
            },
            {
              "name": "https://bugzilla.mozilla.org/show_bug.cgi?id=1678545",
              "refsource": "MISC",
              "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1678545"
            },
            {
              "name": "GLSA-202104-10",
              "refsource": "GENTOO",
              "url": "https://security.gentoo.org/glsa/202104-10"
            }
          ]
        }
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe",
    "assignerShortName": "mozilla",
    "cveId": "CVE-2021-23971",
    "datePublished": "2021-02-26T01:55:29.000Z",
    "dateReserved": "2021-01-13T00:00:00.000Z",
    "dateUpdated": "2024-08-03T19:14:09.872Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1"
}

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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.