{"id":"CVE-2025-4086","title":"A specially crafted filename containing a large number of encoded newline characters could obscure the file's extension when displayed in the download dialog.\n*This bug only affects Thunderbird for Android","summary":"A specially crafted filename containing a large number of encoded newline characters could obscure the file's extension when displayed in the download dialog.\n*This bug only affects Thunderbird for Android. Other versions of Thunderbird …","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-451"],"vendor":"mozilla","product":"firefox","affected":["firefox < 138.0","thunderbird < 138.0"],"patched":["firefox 138.0","thunderbird 138.0"],"published":"2025-04-29","updated":"2026-09-30","sourceUpdated":"2026-09-30T18:10:00.190","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2025-4086","references":[{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=1945705","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-28/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-31/","label":"security@mozilla.org"}],"tags":["nvd"],"epss":0.0029,"epssPercentile":0.19479,"ingestedAt":"2026-09-30T18:17:24.434Z","slug":"CVE-2025-4086","body":"## Overview\n\nA specially crafted filename containing a large number of encoded newline characters could obscure the file's extension when displayed in the download dialog.\n*This bug only affects Thunderbird for Android. Other versions of Thunderbird are unaffected.*. This vulnerability was fixed in Firefox 138 and Thunderbird 138.\n\n## Affected\n\n- `firefox < 138.0`\n- `thunderbird < 138.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `firefox 138.0`\n- `thunderbird 138.0`","depth":"sunlit","depthScore":36,"depthScoreParts":{"impact":35.8,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}