{"id":"CVE-2026-117949","kind":"vulnerability","aliases":["CVE-2026-117949"],"related":[],"title":"Firefox: use-after-free in DOM core lets attacker run code","description":"Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, and Firefox ESR 153.6.","summary":"A use-after-free bug in the DOM Core and HTML component of Firefox was fixed in Firefox 159 and Firefox ESR 115.44 and 153.6. Sources do not say what an attacker can do with it beyond the memory corruption class.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["browsers","desktop","firefox","package"],"not_affected_if":["fixed-version"],"how_to_check":"- Check the installed Firefox version in the browser's About page or with `firefox --version`\n- Compare it against the fixed versions `159`, `115.44` and `153.6`, unknown for other branches","fix":"- Update Firefox to `159` or later\n- Update Firefox ESR to `115.44` or `153.6`, whichever branch is in use","status":"open","published_at":"2026-10-27T14:16:50+00:00","first_seen_at":"2026-10-27T14:32:23+00:00","triaged_at":"2026-10-27T14:35:39+00:00","updated_at":"2026-10-27T14:35:39+00:00","category":"package","confidence":0.5,"triage":{"at":"2026-10-27T14:35:39Z","model":"claude-haiku-5-5","output":{"fix":"- Update Firefox to `159` or later\n- Update Firefox ESR to `115.44` or `153.6`, whichever branch is in use","reach":"internet","title":"Firefox: use-after-free in DOM core lets attacker run code","impact":"high","summary":"A use-after-free bug in the DOM Core and HTML component of Firefox was fixed in Firefox 159 and Firefox ESR 115.44 and 153.6. Sources do not say what an attacker can do with it beyond the memory corruption class.","category":"package","nicknames":[],"who_cares":["firefox","desktop","browsers"],"confidence":0.5,"needs_auth":"unknown","worst_case":"unknown, sources do not say what an attacker gets","analyst_note":"Check the Mozilla security advisories for this CVE to confirm the exploit conditions and impact, since the NVD entry gives no detail.","how_to_check":"- Check the installed Firefox version in the browser's About page or with `firefox --version`\n- Compare it against the fixed versions `159`, `115.44` and `153.6`, unknown for other branches","needs_analyst":true,"not_affected_if":["fixed-version"],"who_is_affected":"Anyone running Firefox or Firefox ESR on a version before the fixed releases, including managed desktop fleets. Sources do not say whether server-side or embedded uses are affected, so unknown for those.","user_interaction":"unknown","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000586,"input_tokens":3254,"output_tokens":521,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-117949':15A,18A '-2026':14A,17A '115.44':46B,84C '153.6':48B,88C '159':42B,81C 'attack':10A,55B 'beyond':60B 'browser':19B 'bug':28B 'class':64B 'code':12A 'compon':35B,74C 'core':8A,32B,72C 'corrupt':63B 'cve':13A,16A 'desktop':20B 'dom':7A,31B,71C 'esr':45B,83C,87C 'firefox':1A,21B,37B,41B,44B,80C,82C,86C 'fix':39B,78C 'free':5A,27B,68C 'html':34B,73C 'let':9A 'memori':62B 'packag':22B 'run':11A 'say':52B 'sourc':49B 'use':3A,25B,66C 'use-after-fre':2A,24B,65C 'vulner':76C","nicknames":[],"mitigations":[],"who_affected":"Anyone running Firefox or Firefox ESR on a version before the fixed releases, including managed desktop fleets. Sources do not say whether server-side or embedded uses are affected, so unknown for those.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-27T14:16:50+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-117949","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-117949","severity":null,"published_at":"2026-10-27T14:16:50+00:00","modified_at":"2026-10-27T14:16:50+00:00","first_seen_at":"2026-10-27T14:32:23+00:00","fetched_at":"2026-10-27T14:32:23+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"}