{"id":"CVE-2026-124877","kind":"vulnerability","aliases":["CVE-2026-124877"],"related":[],"title":"Firefox: use-after-free in Layout Positioned component fixed in 160","description":"Use-after-free in the Layout: Positioned component. This vulnerability was fixed in Firefox 160, Firefox ESR 115.45, and Firefox ESR 153.7.","summary":"A use-after-free bug in Firefox's Layout: Positioned component lets memory be reused after it is freed. An attacker who gets a user to load a crafted page could potentially run code in the browser, though the sources do not state this.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["browser","firefox","runtime"],"not_affected_if":["already-on-fixed-version"],"how_to_check":"- Check the Firefox version in Help > About Firefox; affected builds are older than `160`, `115.45` (ESR) and `153.7` (ESR).","fix":"- Firefox: `160`\n- Firefox ESR: `115.45`\n- Firefox ESR: `153.7`","status":"open","published_at":"2026-11-10T14:17:20+00:00","first_seen_at":"2026-11-10T14:22:14+00:00","triaged_at":"2026-11-10T14:26:18+00:00","updated_at":"2026-11-10T14:26:18+00:00","category":"runtime","confidence":0.5,"triage":{"at":"2026-11-10T14:26:18Z","model":"claude-haiku-5-5","output":{"fix":"- Firefox: `160`\n- Firefox ESR: `115.45`\n- Firefox ESR: `153.7`","reach":"internet","title":"Firefox: use-after-free in Layout Positioned component fixed in 160","impact":"high","summary":"A use-after-free bug in Firefox's Layout: Positioned component lets memory be reused after it is freed. An attacker who gets a user to load a crafted page could potentially run code in the browser, though the sources do not state this.","audience":"everyone","category":"runtime","nicknames":[],"who_cares":["firefox","browser"],"confidence":0.5,"fix_status":"available","needs_auth":"unknown","worst_case":"unknown; memory corruption could allow code execution in the browser","analyst_note":"Sources give only the NVD entry and a one-line description; check the Mozilla security advisory for trigger conditions and severity.","how_to_check":"- Check the Firefox version in Help > About Firefox; affected builds are older than `160`, `115.45` (ESR) and `153.7` (ESR).\n- unknown for any further checks","plain_action":"Update Firefox to version 160 or the ESR versions 115.45 or 153.7 through Help > About Firefox.","product_name":"","needs_analyst":true,"not_affected_if":["already-on-fixed-version"],"who_is_affected":"Anyone running a Firefox build older than the fixed versions, including desktop users on the affected release lines. The sources do not say which configurations or page types trigger the flaw, so unknown.","user_interaction":"unknown","product_ecosystem":"","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000728,"input_tokens":4486,"output_tokens":559,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-124877':15A,18A '-2026':14A,17A '115.45':84C '153.7':88C '160':12A,81C 'attack':43B 'browser':19B,59B 'bug':27B 'code':56B 'compon':9A,33B,74C 'could':53B 'craft':51B 'cve':13A,16A 'esr':83C,87C 'firefox':1A,20B,29B,80C,82C,86C 'fix':10A,78C 'free':5A,26B,69C 'freed':41B 'get':45B 'layout':7A,31B,72C 'let':34B 'load':49B 'memori':35B 'page':52B 'posit':8A,32B,73C 'potenti':54B 'reus':37B 'run':55B 'runtim':21B 'sourc':62B 'state':65B 'though':60B 'use':3A,24B,67C 'use-after-fre':2A,23B,66C 'user':47B 'vulner':76C","nicknames":[],"mitigations":[],"who_affected":"Anyone running a Firefox build older than the fixed versions, including desktop users on the affected release lines. The sources do not say which configurations or page types trigger the flaw, so unknown.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"everyone","plain_action":"Update Firefox to version 160 or the ESR versions 115.45 or 153.7 through Help > About Firefox.","pkeys":[],"ptokens":[],"labels":["browser","firefox","runtime","unknown"],"campaign_type":null,"search_a":"'-124877':15A,18A '-2026':14A,17A '160':12A 'compon':9A 'cve':13A,16A 'firefox':1A 'fix':10A 'free':5A 'layout':7A 'posit':8A 'use':3A 'use-after-fre':2A","search_b":"'attack':43B 'browser':19B,59B 'bug':27B 'code':56B 'compon':33B 'could':53B 'craft':51B 'firefox':20B,29B 'free':26B 'freed':41B 'get':45B 'layout':31B 'let':34B 'load':49B 'memori':35B 'page':52B 'posit':32B 'potenti':54B 'reus':37B 'run':55B 'runtim':21B 'sourc':62B 'state':65B 'though':60B 'use':24B 'use-after-fre':23B 'user':47B","search_c":"'115.45':84C '153.7':88C '160':81C 'compon':74C 'esr':83C,87C 'firefox':80C,82C,86C 'fix':78C 'free':69C 'layout':72C 'posit':73C 'use':67C 'use-after-fre':66C 'vulner':76C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-10T14:17:20+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-124877","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-124877","severity":null,"published_at":"2026-11-10T14:17:20+00:00","modified_at":"2026-11-10T14:17:20+00:00","first_seen_at":"2026-11-10T14:22:14+00:00","fetched_at":"2026-11-10T14:22:14+00:00","note":null}],"documents":[],"disclosures":[],"exploit_sources":[],"notice":"Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai"}