{"id":"CVE-2026-117953","kind":"vulnerability","aliases":["CVE-2026-117953"],"related":[],"title":"Firefox: DOM use-after-free bug fixed in Firefox 159","description":"Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 159 and Firefox ESR 153.6.","summary":"A use-after-free flaw in the DOM Core and HTML component of Firefox can corrupt memory when a page triggers it. The sources do not say what an attacker can achieve beyond that.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["browsers","desktop","firefox","other"],"not_affected_if":["already-updated-browser"],"how_to_check":"- Check the installed Firefox version in the browser's About page or with `firefox --version`\n- Check the ESR version in use against `153.6`","fix":"- Update Firefox to `159` or later\n- Update Firefox ESR to `153.6` or later","status":"open","published_at":"2026-10-27T14:16:51+00:00","first_seen_at":"2026-10-27T14:32:23+00:00","triaged_at":"2026-10-27T14:35:35+00:00","updated_at":"2026-10-27T14:35:35+00:00","category":"other","confidence":0.4,"triage":{"at":"2026-10-27T14:35:35Z","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: DOM use-after-free bug fixed in Firefox 159","impact":"medium","summary":"A use-after-free flaw in the DOM Core and HTML component of Firefox can corrupt memory when a page triggers it. The sources do not say what an attacker can achieve beyond that.","category":"other","nicknames":[],"who_cares":["firefox","browsers","desktop"],"confidence":0.4,"needs_auth":"unknown","worst_case":"unknown","analyst_note":"Check the Mozilla security advisory for this CVE to confirm impact, trigger conditions and whether it is exploited in the wild.","how_to_check":"- Check the installed Firefox version in the browser's About page or with `firefox --version`\n- Check the ESR version in use against `153.6`","needs_analyst":true,"not_affected_if":["already-updated-browser"],"who_is_affected":"Anyone running Firefox or Firefox ESR builds older than the fixed versions. The sources do not say whether specific configurations or content are needed to trigger it.","user_interaction":"unknown","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000547,"input_tokens":3242,"output_tokens":446,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-117953':14A,17A '-2026':13A,16A '153.6':75C '159':11A,71C 'achiev':53B 'attack':51B 'beyond':54B 'browser':18B 'bug':7A 'compon':33B,64C 'core':30B,62C 'corrupt':37B 'cve':12A,15A 'desktop':19B 'dom':2A,29B,61C 'esr':74C 'firefox':1A,10A,20B,35B,70C,73C 'fix':8A,68C 'flaw':26B 'free':6A,25B,58C 'html':32B,63C 'memori':38B 'page':41B 'say':48B 'sourc':45B 'trigger':42B 'use':4A,23B,56C 'use-after-fre':3A,22B,55C 'vulner':66C","nicknames":[],"mitigations":[],"who_affected":"Anyone running Firefox or Firefox ESR builds older than the fixed versions. The sources do not say whether specific configurations or content are needed to trigger it.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-27T14:16:51+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-117953","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-117953","severity":null,"published_at":"2026-10-27T14:16:51+00:00","modified_at":"2026-10-27T14:16:51+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"}