{"id":"CVE-2025-6427","title":"An attacker was able to bypass the `connect-src` directive of a Content Security Policy by manipulating subdocuments","summary":"An attacker was able to bypass the `connect-src` directive of a Content Security Policy by manipulating subdocuments. This would have also hidden the connections from the Network tab in Devtools. This vulnerability was fixed in Firefox 1…","severity":"critical","cvss":9.1,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","cwe":["CWE-693"],"vendor":"mozilla","product":"firefox","affected":["firefox < 140.0"],"patched":["firefox 140.0"],"published":"2025-06-24","updated":"2026-09-30","sourceUpdated":"2026-09-30T18:10:00.190","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2025-6427","references":[{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=1966927","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-51/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-54/","label":"security@mozilla.org"}],"tags":["nvd"],"epss":0.00368,"epssPercentile":0.28268,"ingestedAt":"2026-09-30T18:17:24.443Z","slug":"CVE-2025-6427","body":"## Overview\n\nAn attacker was able to bypass the `connect-src` directive of a Content Security Policy by manipulating subdocuments. This would have also hidden the connections from the Network tab in Devtools. This vulnerability was fixed in Firefox 140 and Thunderbird 140.\n\n## Affected\n\n- `firefox < 140.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `firefox 140.0`","depth":"midnight","depthScore":50,"depthScoreParts":{"impact":50.1,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}