{"id":"CVE-2025-6435","title":"If a user saved a response from the Network tab in Devtools using the Save As context menu option, that file may not have been saved with the `.download` file extension","summary":"If a user saved a response from the Network tab in Devtools using the Save As context menu option, that file may not have been saved with the `.download` file extension. This could have led to the user inadvertently running a malicious e…","severity":"high","cvss":8.1,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-434"],"vendor":"mozilla","product":"firefox","affected":["firefox < 140.0","thunderbird < 140.0"],"patched":["firefox 140.0","thunderbird 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-2025-6435","references":[{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=1950056","label":"security@mozilla.org"},{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=1961777","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":0.00457,"epssPercentile":0.37292,"ingestedAt":"2026-09-30T18:17:24.446Z","slug":"CVE-2025-6435","body":"## Overview\n\nIf a user saved a response from the Network tab in Devtools using the Save As context menu option, that file may not have been saved with the `.download` file extension. This could have led to the user inadvertently running a malicious executable. This vulnerability was fixed in Firefox 140 and Thunderbird 140.\n\n## Affected\n\n- `firefox < 140.0`\n- `thunderbird < 140.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `firefox 140.0`\n- `thunderbird 140.0`","depth":"twilight","depthScore":45,"depthScoreParts":{"impact":44.6,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}