{"id":"CVE-2025-6434","title":"The exception page for the HTTPS-Only feature, displayed when a website is opened via HTTP, lacked an anti-clickjacking delay, potentially allowing an attacker to trick a user into granting an exception and loading a webpage over HTTP","summary":"The exception page for the HTTPS-Only feature, displayed when a website is opened via HTTP, lacked an anti-clickjacking delay, potentially allowing an attacker to trick a user into granting an exception and loading a webpage over HTTP. T…","severity":"medium","cvss":4.3,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N","cwe":["CWE-1021"],"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-2025-6434","references":[{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=1955182","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":0.00283,"epssPercentile":0.1873,"ingestedAt":"2026-09-30T18:17:24.445Z","slug":"CVE-2025-6434","body":"## Overview\n\nThe exception page for the HTTPS-Only feature, displayed when a website is opened via HTTP, lacked an anti-clickjacking delay, potentially allowing an attacker to trick a user into granting an exception and loading a webpage over HTTP. 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":"sunlit","depthScore":24,"depthScoreParts":{"impact":23.7,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}