{"api_version":"1","generated_at":"2026-07-23T09:48:02+00:00","cve":"CVE-2025-5271","urls":{"html":"https://cve.report/CVE-2025-5271","api":"https://cve.report/api/cve/CVE-2025-5271.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2025-5271","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2025-5271"},"summary":{"title":"Devtools' preview ignored CSP headers","description":"Previewing a response in Devtools ignored CSP headers, which could have allowed content injection attacks. This vulnerability was fixed in Firefox 139 and Thunderbird 139.","state":"PUBLISHED","assigner":"mozilla","published_at":"2025-05-27 13:15:22","updated_at":"2026-04-13 15:17:05"},"problem_types":["CWE-116","CWE-116 CWE-116 Improper Encoding or Escaping of Output"],"metrics":[{"version":"3.1","source":"ADP","type":"DECLARED","score":"6.5","severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","data":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":6.5,"baseSeverity":"MEDIUM","confidentialityImpact":"LOW","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","version":"3.1"}},{"version":"3.1","source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","type":"Secondary","score":"6.5","severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","baseScore":6.5,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"LOW","integrityImpact":"LOW","availabilityImpact":"NONE"}}],"references":[{"url":"https://www.mozilla.org/security/advisories/mfsa2025-42/","name":"https://www.mozilla.org/security/advisories/mfsa2025-42/","refsource":"security@mozilla.org","tags":["Vendor Advisory"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-45/","name":"https://www.mozilla.org/security/advisories/mfsa2025-45/","refsource":"security@mozilla.org","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=1920348","name":"https://bugzilla.mozilla.org/show_bug.cgi?id=1920348","refsource":"security@mozilla.org","tags":["Permissions Required"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2025-5271","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2025-5271","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Mozilla","product":"Firefox","version":"unaffected 139 * rpm","platforms":[]},{"source":"CNA","vendor":"Mozilla","product":"Thunderbird","version":"unaffected 139 * rpm","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[{"source":"CNA","value":"Satoki Tsuji","lang":"en"}],"nvd_cpes":[{"cve_year":"2025","cve_id":"5271","vulnerable":"1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"a","cpe4":"mozilla","cpe5":"firefox","cpe6":"*","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"}],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2025","cve_id":"5271","cve":"CVE-2025-5271","epss":"0.002820000","percentile":"0.516070000","score_date":"2026-04-15","updated_at":"2026-04-16 00:13:56"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"adp":[{"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":6.5,"baseSeverity":"MEDIUM","confidentialityImpact":"LOW","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","version":"3.1"}},{"other":{"content":{"id":"CVE-2025-5271","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","timestamp":"2025-05-27T17:36:12.567350Z","version":"2.0.3"},"type":"ssvc"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-116","description":"CWE-116 Improper Encoding or Escaping of Output","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2025-05-27T17:37:33.657Z","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP"},"title":"CISA ADP Vulnrichment"}],"cna":{"affected":[{"product":"Firefox","vendor":"Mozilla","versions":[{"lessThanOrEqual":"*","status":"unaffected","version":"139","versionType":"rpm"}]},{"product":"Thunderbird","vendor":"Mozilla","versions":[{"lessThanOrEqual":"*","status":"unaffected","version":"139","versionType":"rpm"}]}],"credits":[{"lang":"en","value":"Satoki Tsuji"}],"descriptions":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"Previewing a response in Devtools ignored CSP headers, which could have allowed content injection attacks. This vulnerability was fixed in Firefox 139 and Thunderbird 139."}],"value":"Previewing a response in Devtools ignored CSP headers, which could have allowed content injection attacks. This vulnerability was fixed in Firefox 139 and Thunderbird 139."}],"providerMetadata":{"dateUpdated":"2026-04-13T14:30:48.968Z","orgId":"f16b083a-5664-49f3-a51e-8d479e5ed7fe","shortName":"mozilla"},"references":[{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=1920348"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-42/"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-45/"}],"title":"Devtools' preview ignored CSP headers"}},"cveMetadata":{"assignerOrgId":"f16b083a-5664-49f3-a51e-8d479e5ed7fe","assignerShortName":"mozilla","cveId":"CVE-2025-5271","datePublished":"2025-05-27T12:29:29.404Z","dateReserved":"2025-05-27T12:29:29.015Z","dateUpdated":"2026-04-13T14:30:48.968Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2025-05-27 13:15:22","lastModifiedDate":"2026-04-13 15:17:05","problem_types":["CWE-116","CWE-116 CWE-116 Improper Encoding or Escaping of Output"],"metrics":{"cvssMetricV31":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","baseScore":6.5,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"LOW","integrityImpact":"LOW","availabilityImpact":"NONE"},"exploitabilityScore":3.9,"impactScore":2.5}]},"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*","versionEndExcluding":"139.0","matchCriteriaId":"82C74587-41B7-49DB-8B9D-99DE41506023"}]}]}]},"legacy_mitre":{"record":{"CveYear":"2025","CveId":"5271","Ordinal":"1","Title":"Devtools' preview ignored CSP headers","CVE":"CVE-2025-5271","Year":"2025"},"notes":[{"CveYear":"2025","CveId":"5271","Ordinal":"1","NoteData":"Previewing a response in Devtools ignored CSP headers, which could have allowed content injection attacks. This vulnerability was fixed in Firefox 139 and Thunderbird 139.","Type":"Description","Title":"Devtools' preview ignored CSP headers"}]}}}