{"api_version":"1","generated_at":"2026-04-23T04:10:54+00:00","cve":"CVE-2021-23986","urls":{"html":"https://cve.report/CVE-2021-23986","api":"https://cve.report/api/cve/CVE-2021-23986.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2021-23986","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-23986"},"summary":{"title":"CVE-2021-23986","description":"A malicious extension with the 'search' permission could have installed a new search engine whose favicon referenced a cross-origin URL. The response to this cross-origin request could have been read by the extension, allowing a same-origin policy bypass by the extension, which should not have cross-origin permissions. This cross-origin request was made without cookies, so the sensitive information disclosed by the violation was limited to local-network resources or resources that perform IP-based authentication. 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The response to this cross-origin request could have been read by the extension, allowing a same-origin policy bypass by the extension, which should not have cross-origin permissions. This cross-origin request was made without cookies, so the sensitive information disclosed by the violation was limited to local-network resources or resources that perform IP-based authentication. This vulnerability affects Firefox < 87."}]}},"nvd":{"publishedDate":"2021-03-31 14:15:00","lastModifiedDate":"2021-08-06 18:18:00","problem_types":["CWE-346"],"metrics":{"baseMetricV3":{"cvssV3":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"REQUIRED","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"NONE","availabilityImpact":"NONE","baseScore":6.5,"baseSeverity":"MEDIUM"},"exploitabilityScore":2.8,"impactScore":3.6},"baseMetricV2":{"cvssV2":{"version":"2.0","vectorString":"AV:N/AC:M/Au:N/C:P/I:N/A:N","accessVector":"NETWORK","accessComplexity":"MEDIUM","authentication":"NONE","confidentialityImpact":"PARTIAL","integrityImpact":"NONE","availabilityImpact":"NONE","baseScore":4.3},"severity":"MEDIUM","exploitabilityScore":8.6,"impactScore":2.9,"acInsufInfo":false,"obtainAllPrivilege":false,"obtainUserPrivilege":false,"obtainOtherPrivilege":false,"userInteractionRequired":true}},"configurations":{"CVE_data_version":"4.0","nodes":[{"operator":"OR","children":[],"cpe_match":[{"vulnerable":true,"cpe23Uri":"cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*","versionEndExcluding":"87.0","cpe_name":[]}]}]}},"legacy_mitre":{"record":{"CveYear":"2021","CveId":"23986","Ordinal":"198742","Title":"CVE-2021-23986","CVE":"CVE-2021-23986","Year":"2021"},"notes":[{"CveYear":"2021","CveId":"23986","Ordinal":"1","NoteData":"A malicious extension with the 'search' permission could have installed a new search engine whose favicon referenced a cross-origin URL. The response to this cross-origin request could have been read by the extension, allowing a same-origin policy bypass by the extension, which should not have cross-origin permissions. This cross-origin request was made without cookies, so the sensitive information disclosed by the violation was limited to local-network resources or resources that perform IP-based authentication. This vulnerability affects Firefox < 87.","Type":"Description","Title":null},{"CveYear":"2021","CveId":"23986","Ordinal":"2","NoteData":"2021-03-31","Type":"Other","Title":"Published"},{"CveYear":"2021","CveId":"23986","Ordinal":"3","NoteData":"2021-06-24","Type":"Other","Title":"Modified"}]}}}