{"id":"CVE-2026-117954","kind":"vulnerability","aliases":["CVE-2026-117954"],"related":[],"title":"Firefox: use-after-free in Layout Positioned component fixed in 159","description":"Use-after-free in the Layout: Positioned 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 Layout: Positioned component of Firefox lets memory be reused after it is freed. Sources do not say what an attacker gets beyond that, and no severity is given.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["browsers","desktop","firefox","runtime"],"not_affected_if":["patched-version"],"how_to_check":"- Check the installed Firefox version in the browser's About page or with `firefox --version`\n- Check ESR installs with `firefox --version` against the ESR branch in use","fix":"- Update Firefox to `159` or later\n- Update Firefox ESR 115 to `115.44` or later\n- Update Firefox ESR 153 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":"2026-10-27T14:35:34+00:00","updated_at":"2026-10-27T14:35:34+00:00","category":"runtime","confidence":0.5,"triage":{"at":"2026-10-27T14:35:34Z","model":"claude-haiku-5-5","output":{"fix":"- Update Firefox to `159` or later\n- Update Firefox ESR 115 to `115.44` or later\n- Update Firefox ESR 153 to `153.6` or later","reach":"unknown","title":"Firefox: use-after-free in Layout Positioned component fixed in 159","impact":"high","summary":"A use-after-free bug in the Layout: Positioned component of Firefox lets memory be reused after it is freed. Sources do not say what an attacker gets beyond that, and no severity is given.","category":"runtime","nicknames":[],"who_cares":["firefox","desktop","browsers"],"confidence":0.5,"needs_auth":"unknown","worst_case":"unknown","analyst_note":"Check the Mozilla security advisory for the Firefox 159 release to confirm trigger conditions and impact.","how_to_check":"- Check the installed Firefox version in the browser's About page or with `firefox --version`\n- Check ESR installs with `firefox --version` against the ESR branch in use","needs_analyst":true,"not_affected_if":["patched-version"],"who_is_affected":"Anyone running desktop or ESR builds of Firefox older than the fixed versions is exposed. Servers and teams that do not run Firefox, or that run only patched builds, can skip it. unknown for whether the flaw is reachable through web content.","user_interaction":"unknown","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000574,"input_tokens":3250,"output_tokens":498,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-117954':15A,18A '-2026':14A,17A '115.44':77C '153.6':81C '159':12A,74C 'attack':50B 'beyond':52B 'browser':19B 'bug':28B 'compon':9A,33B,67C 'cve':13A,16A 'desktop':20B 'esr':76C,80C 'firefox':1A,21B,35B,73C,75C,79C 'fix':10A,71C 'free':5A,27B,62C 'freed':43B 'get':51B 'given':58B 'layout':7A,31B,65C 'let':36B 'memori':37B 'posit':8A,32B,66C 'reus':39B 'runtim':22B 'say':47B 'sever':56B 'sourc':44B 'use':3A,25B,60C 'use-after-fre':2A,24B,59C 'vulner':69C","nicknames":[],"mitigations":[],"who_affected":"Anyone running desktop or ESR builds of Firefox older than the fixed versions is exposed. Servers and teams that do not run Firefox, or that run only patched builds, can skip it. unknown for whether the flaw is reachable through web content.","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-2026-117954","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-117954","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"}