{"id":"CVE-2025-5271","title":"Previewing a response in Devtools ignored CSP headers, which could have allowed content injection attacks","summary":"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.","severity":"medium","cvss":6.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","cwe":["CWE-116"],"vendor":"mozilla","product":"firefox","affected":["firefox < 139.0"],"patched":["firefox 139.0"],"published":"2025-05-27","updated":"2026-09-30","sourceUpdated":"2026-09-30T18:10:00.190","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2025-5271","references":[{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=1920348","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-42/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-45/","label":"security@mozilla.org"}],"tags":["nvd"],"epss":0.00305,"epssPercentile":0.20975,"ingestedAt":"2026-09-30T18:17:24.441Z","slug":"CVE-2025-5271","body":"## Overview\n\nPreviewing a response in Devtools ignored CSP headers, which could have allowed content injection attacks. This vulnerability was fixed in Firefox 139 and Thunderbird 139.\n\n## Affected\n\n- `firefox < 139.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `firefox 139.0`","depth":"sunlit","depthScore":36,"depthScoreParts":{"impact":35.8,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}