{"id":"CVE-2026-124940","kind":"vulnerability","aliases":["CVE-2026-124940"],"related":[],"title":"Firefox: File Handling mitigation bypass fixed in versions 160 and ESR 153.7","description":"Mitigation bypass in the File Handling component. This vulnerability was fixed in Firefox 160 and Firefox ESR 153.7.","summary":"A bypass of a security mitigation in Firefox's File Handling component was fixed in Firefox 160 and Firefox ESR 153.7. The sources do not say what an attacker can do after bypassing it.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["browser","firefox","runtime"],"not_affected_if":["already-on-fixed-version"],"how_to_check":"- Check the installed Firefox version in the browser's About page or with the product's version output.\n- Compare against `160` for Firefox and `153.7` for Firefox ESR.","fix":"- Firefox: `160`\n- Firefox ESR: `153.7`","status":"open","published_at":"2026-11-10T14:17:28+00:00","first_seen_at":"2026-11-10T14:22:19+00:00","triaged_at":"2026-11-10T14:24:10+00:00","updated_at":"2026-11-10T14:24:10+00:00","category":"runtime","confidence":0.4,"triage":{"at":"2026-11-10T14:24:10Z","model":"claude-haiku-5-5","output":{"fix":"- Firefox: `160`\n- Firefox ESR: `153.7`","reach":"unknown","title":"Firefox: File Handling mitigation bypass fixed in versions 160 and ESR 153.7","impact":"medium","summary":"A bypass of a security mitigation in Firefox's File Handling component was fixed in Firefox 160 and Firefox ESR 153.7. The sources do not say what an attacker can do after bypassing it.","audience":"everyone","category":"runtime","nicknames":[],"who_cares":["firefox","browser"],"confidence":0.4,"fix_status":"available","needs_auth":"unknown","worst_case":"unknown; sources do not describe the impact beyond the bypass","analyst_note":"Sources give no detail on the bypassed mitigation or the attack path; check the Mozilla security advisory for the File Handling entry.","how_to_check":"- Check the installed Firefox version in the browser's About page or with the product's version output.\n- Compare against `160` for Firefox and `153.7` for Firefox ESR.","plain_action":"Update Firefox to version 160 or Firefox ESR to 153.7 or later.","product_name":"","needs_analyst":true,"not_affected_if":["already-on-fixed-version"],"who_is_affected":"unknown","user_interaction":"unknown","product_ecosystem":"","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000687,"input_tokens":4470,"output_tokens":481,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-124940':15A,18A '-2026':14A,17A '153.7':12A,42B,72C '160':9A,38B,68C 'attack':50B 'browser':19B 'bypass':5A,23B,54B,56C 'compon':33B,61C 'cve':13A,16A 'esr':11A,41B,71C 'file':2A,31B,59C 'firefox':1A,20B,29B,37B,40B,67C,70C 'fix':6A,35B,65C 'handl':3A,32B,60C 'mitig':4A,27B,55C 'runtim':21B 'say':47B 'secur':26B 'sourc':44B 'version':8A 'vulner':63C","nicknames":[],"mitigations":[],"who_affected":null,"tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"everyone","plain_action":"Update Firefox to version 160 or Firefox ESR to 153.7 or later.","pkeys":[],"ptokens":[],"labels":["browser","firefox","runtime","unknown"],"campaign_type":null,"search_a":"'-124940':15A,18A '-2026':14A,17A '153.7':12A '160':9A 'bypass':5A 'cve':13A,16A 'esr':11A 'file':2A 'firefox':1A 'fix':6A 'handl':3A 'mitig':4A 'version':8A","search_b":"'153.7':42B '160':38B 'attack':50B 'browser':19B 'bypass':23B,54B 'compon':33B 'esr':41B 'file':31B 'firefox':20B,29B,37B,40B 'fix':35B 'handl':32B 'mitig':27B 'runtim':21B 'say':47B 'secur':26B 'sourc':44B","search_c":"'153.7':72C '160':68C 'bypass':56C 'compon':61C 'esr':71C 'file':59C 'firefox':67C,70C 'fix':65C 'handl':60C 'mitig':55C 'vulner':63C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-10T14:17:28+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-124940","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-124940","severity":null,"published_at":"2026-11-10T14:17:28+00:00","modified_at":"2026-11-10T14:17:28+00:00","first_seen_at":"2026-11-10T14:22:19+00:00","fetched_at":"2026-11-10T14:22:19+00:00","note":null}],"documents":[],"disclosures":[],"exploit_sources":[],"notice":"Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai"}