{"id":"CVE-2026-117864","kind":"vulnerability","aliases":["CVE-2026-117864"],"related":[],"title":"Firefox: Form Manager sandbox escape fixed in Firefox 159","description":"Sandbox escape in the Form Manager component. This vulnerability was fixed in Firefox 159 and Firefox ESR 153.6.","summary":"A flaw in the Form Manager component of Firefox allows escape from the browser sandbox. The sources do not say what an attacker gains after escaping.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["desktop-browsers","firefox","other"],"not_affected_if":["already-updated"],"how_to_check":"- Check the installed Firefox version: `firefox --version`\n- Confirm whether Firefox ESR is in use and its version: `firefox --version` on the ESR install","fix":"- Update Firefox to `159` or later\n- Update Firefox ESR to `153.6` or later","status":"open","published_at":"2026-10-27T14:16:40+00:00","first_seen_at":"2026-10-27T14:32:21+00:00","triaged_at":"2026-10-27T14:39:21+00:00","updated_at":"2026-10-27T14:39:21+00:00","category":"other","confidence":0.5,"triage":{"at":"2026-10-27T14:39:21Z","model":"claude-haiku-5-5","output":{"fix":"- Update Firefox to `159` or later\n- Update Firefox ESR to `153.6` or later","reach":"unknown","title":"Firefox: Form Manager sandbox escape fixed in Firefox 159","impact":"high","summary":"A flaw in the Form Manager component of Firefox allows escape from the browser sandbox. The sources do not say what an attacker gains after escaping.","category":"other","nicknames":[],"who_cares":["firefox","desktop-browsers"],"confidence":0.5,"needs_auth":"unknown","worst_case":"unknown; sandbox escape could let attacker-controlled code reach the wider system","analyst_note":"Check the Mozilla security advisory for the Form Manager sandbox escape to confirm trigger conditions and user interaction.","how_to_check":"- Check the installed Firefox version: `firefox --version`\n- Confirm whether Firefox ESR is in use and its version: `firefox --version` on the ESR install","needs_analyst":true,"not_affected_if":["already-updated"],"who_is_affected":"Anyone running Firefox or Firefox ESR older than the fixed versions. The sources do not say whether specific configurations or content are needed to trigger the flaw.","user_interaction":"unknown","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000554,"input_tokens":3234,"output_tokens":462,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-117864':12A,15A '-2026':11A,14A '153.6':63C '159':9A,59C 'allow':29B 'attack':42B 'browser':18B,33B 'compon':26B,52C 'cve':10A,13A 'desktop':17B 'desktop-brows':16B 'escap':5A,30B,45B,47C 'esr':62C 'firefox':1A,8A,19B,28B,58C,61C 'fix':6A,56C 'flaw':21B 'form':2A,24B,50C 'gain':43B 'manag':3A,25B,51C 'sandbox':4A,34B,46C 'say':39B 'sourc':36B 'vulner':54C","nicknames":[],"mitigations":[],"who_affected":"Anyone running Firefox or Firefox ESR older than the fixed versions. The sources do not say whether specific configurations or content are needed to trigger the flaw.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-27T14:16:40+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-117864","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-117864","severity":null,"published_at":"2026-10-27T14:16:40+00:00","modified_at":"2026-10-27T14:16:40+00:00","first_seen_at":"2026-10-27T14:32:21+00:00","fetched_at":"2026-10-27T14:32:21+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}