{"id":"CVE-2026-117919","kind":"vulnerability","aliases":["CVE-2026-117919"],"related":[],"title":"Firefox: use-after-free in DOM core and HTML lets attackers 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 the ESR releases 115.44 and 153.6. Use-after-free flaws of this kind can let a crafted web page corrupt memory and may allow code execution, but the sources do not state the impact.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["browser","desktop","firefox","managed-fleet","runtime"],"not_affected_if":["patched-version"],"how_to_check":"- Check the installed browser version in Firefox via the About Firefox menu, or run `firefox --version` on the machine.\n- Confirm whether the installed version is earlier than `159`, `115.44` or `153.6` for the matching ESR branch.","fix":"- Update Firefox to `159` or later on the current release channel.\n- Update Firefox ESR to `115.44` or `153.6` on the ESR channel, depending on the branch in use.","status":"open","published_at":"2026-10-27T14:16:47+00:00","first_seen_at":"2026-10-27T14:32:22+00:00","triaged_at":"2026-10-27T14:37:19+00:00","updated_at":"2026-10-27T14:37:19+00:00","category":"runtime","confidence":0.5,"triage":{"at":"2026-10-27T14:37:19Z","model":"claude-haiku-5-5","output":{"fix":"- Update Firefox to `159` or later on the current release channel.\n- Update Firefox ESR to `115.44` or `153.6` on the ESR channel, depending on the branch in use.","reach":"internet","title":"Firefox: use-after-free in DOM core and HTML lets attackers 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 the ESR releases 115.44 and 153.6. Use-after-free flaws of this kind can let a crafted web page corrupt memory and may allow code execution, but the sources do not state the impact.","category":"runtime","nicknames":[],"who_cares":["firefox","browser","desktop","managed-fleet"],"confidence":0.5,"needs_auth":"no","worst_case":"Attacker may run code in the browser via a crafted web page.","analyst_note":"Sources say only that it was fixed in Firefox 159 and ESR 115.44/153.6; check the Mozilla security advisory for the exact impact, CVSS score and whether exploitation is known.","how_to_check":"- Check the installed browser version in Firefox via the About Firefox menu, or run `firefox --version` on the machine.\n- Confirm whether the installed version is earlier than `159`, `115.44` or `153.6` for the matching ESR branch.","needs_analyst":true,"not_affected_if":["patched-version"],"who_is_affected":"Anyone running an unpatched Firefox build that renders web content, including desktop installs and managed fleets pinned to ESR. Systems already on Firefox 159, ESR 115.44 or ESR 153.6 or later are not affected by this specific fix. The sources do not say which configurations or page types trigger the bug.","user_interaction":"yes","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000645,"input_tokens":3254,"output_tokens":640,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-117919':17A,20A '-2026':16A,19A '115.44':52B,103C '153.6':54B,107C '159':47B,100C 'allow':73B 'attack':12A 'browser':21B 'bug':33B 'code':14A,74B 'compon':40B,93C 'core':8A,37B,91C 'corrupt':69B 'craft':66B 'cve':15A,18A 'desktop':22B 'dom':7A,36B,90C 'esr':50B,102C,106C 'execut':75B 'firefox':1A,23B,42B,46B,99C,101C,105C 'fix':44B,97C 'flaw':59B 'fleet':26B 'free':5A,32B,58B,87C 'html':10A,39B,92C 'impact':83B 'kind':62B 'let':11A,64B 'manag':25B 'managed-fleet':24B 'may':72B 'memori':70B 'page':68B 'releas':51B 'run':13A 'runtim':27B 'sourc':78B 'state':81B 'use':3A,30B,56B,85C 'use-after-fre':2A,29B,55B,84C 'vulner':95C 'web':67B","nicknames":[],"mitigations":[],"who_affected":"Anyone running an unpatched Firefox build that renders web content, including desktop installs and managed fleets pinned to ESR. Systems already on Firefox 159, ESR 115.44 or ESR 153.6 or later are not affected by this specific fix. The sources do not say which configurations or page types trigger the bug.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-27T14:16:47+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-117919","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-117919","severity":null,"published_at":"2026-10-27T14:16:47+00:00","modified_at":"2026-10-27T14:16:47+00:00","first_seen_at":"2026-10-27T14:32:22+00:00","fetched_at":"2026-10-27T14:32:22+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"}