{"id":"CVE-2025-6425","title":"An attacker who enumerated resources from the WebCompat extension could have obtained a persistent UUID that identified the browser, and persisted between containers and normal/private browsing mode, but not profiles","summary":"An attacker who enumerated resources from the WebCompat extension could have obtained a persistent UUID that identified the browser, and persisted between containers and normal/private browsing mode, but not profiles. This vulnerability …","severity":"medium","cvss":4.3,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N","cwe":["CWE-200"],"vendor":"mozilla","product":"firefox","affected":["firefox < 115.25.0","firefox < 140.0","firefox >= 116.0, < 128.12.0"],"patched":["firefox 128.12.0"],"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-2025-6425","references":[{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=1717672","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-51/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-52/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-53/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-54/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-55/","label":"security@mozilla.org"},{"url":"https://lists.debian.org/debian-lts-announce/2025/06/msg00029.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2025/07/msg00002.html","label":"af854a3a-2127-422b-91ae-364da2661108"}],"tags":["nvd"],"epss":0.0031,"epssPercentile":0.21512,"ingestedAt":"2026-09-30T18:17:24.442Z","slug":"CVE-2025-6425","body":"## Overview\n\nAn attacker who enumerated resources from the WebCompat extension could have obtained a persistent UUID that identified the browser, and persisted between containers and normal/private browsing mode, but not profiles. This vulnerability was fixed in Firefox 140, Firefox ESR 115.25, Firefox ESR 128.12, Thunderbird 140, and Thunderbird 128.12.\n\n## Affected\n\n- `firefox < 115.25.0`\n- `firefox < 140.0`\n- `firefox >= 116.0, < 128.12.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `firefox 128.12.0`","depth":"sunlit","depthScore":24,"depthScoreParts":{"impact":23.7,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}