{"id":"CVE-2026-124903","kind":"vulnerability","aliases":["CVE-2026-124903"],"related":[],"title":"Firefox: use-after-free in IPC lets a sandbox escape happen","description":"Sandbox escape due to use-after-free in the IPC 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 IPC component allows a sandbox escape. An attacker who can run content in the browser could get past the sandbox restrictions meant to contain it.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[{"name":"Firefox","fixed":[],"affected":"","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["desktop-browsers","firefox","other"],"not_affected_if":["fixed-version"],"how_to_check":"- Check the installed Firefox version with `about:support` or the Help menu; compare against the fixed versions below.\n- Check ESR installs against `115.45` and `153.7`.","fix":"- Firefox `160`\n- Firefox ESR `115.45`\n- Firefox ESR `153.7`","status":"open","published_at":"2026-11-10T14:17:23+00:00","first_seen_at":"2026-11-10T14:22:17+00:00","triaged_at":"2026-11-10T14:24:49+00:00","updated_at":"2026-11-10T14:24:49+00:00","category":"other","confidence":0.5,"triage":{"at":"2026-11-10T14:24:49Z","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 IPC lets a sandbox escape happen","impact":"high","summary":"A use-after-free bug in Firefox's IPC component allows a sandbox escape. An attacker who can run content in the browser could get past the sandbox restrictions meant to contain it.","audience":"everyone","category":"other","nicknames":[],"who_cares":["firefox","desktop-browsers"],"confidence":0.5,"fix_status":"available","needs_auth":"unknown","worst_case":"Attacker escapes browser sandbox and reaches the underlying system","analyst_note":"Confirm trigger conditions and affected version ranges from Mozilla's advisory for CVE-2026-124903; sources only give the fixed versions.","how_to_check":"- Check the installed Firefox version with `about:support` or the Help menu; compare against the fixed versions below.\n- Check ESR installs against `115.45` and `153.7`.","plain_action":"Update Firefox to version 160, or to ESR 115.45 or 153.7 if you use the ESR channel: Help > About Firefox.","product_name":"Firefox","needs_analyst":true,"not_affected_if":["fixed-version"],"who_is_affected":"Anyone running a Firefox build older than the fixed versions is exposed, since the flaw is in the browser's own IPC code. Sources do not say whether a specific page or content type is needed to trigger it.","user_interaction":"unknown","product_ecosystem":"vendor","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000743,"input_tokens":4492,"output_tokens":588,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-124903':15A,18A '-2026':14A,17A '115.45':78C '153.7':82C '160':75C 'allow':35B 'attack':40B 'browser':22B,47B 'bug':29B 'compon':34B,68C 'contain':56B 'content':44B 'could':48B 'cve':13A,16A 'desktop':21B 'desktop-brows':20B 'due':59C 'escap':11A,38B,58C 'esr':77C,81C 'firefox':1A,19A,23B,31B,74C,76C,80C 'fix':72C 'free':5A,28B,64C 'get':49B 'happen':12A 'ipc':7A,33B,67C 'let':8A 'meant':54B 'past':50B 'restrict':53B 'run':43B 'sandbox':10A,37B,52B,57C 'use':3A,26B,62C 'use-after-fre':2A,25B,61C 'vulner':70C","nicknames":[],"mitigations":[],"who_affected":"Anyone running a Firefox build older than the fixed versions is exposed, since the flaw is in the browser's own IPC code. Sources do not say whether a specific page or content type is needed to trigger it.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"everyone","plain_action":"Update Firefox to version 160, or to ESR 115.45 or 153.7 if you use the ESR channel: Help > About Firefox.","pkeys":["firefox"],"ptokens":["firefox"],"labels":["desktopbrowsers","firefox","other","unknown","vendor"],"campaign_type":null,"search_a":"'-124903':15A,18A '-2026':14A,17A 'cve':13A,16A 'escap':11A 'firefox':1A,19A 'free':5A 'happen':12A 'ipc':7A 'let':8A 'sandbox':10A 'use':3A 'use-after-fre':2A","search_b":"'allow':35B 'attack':40B 'browser':22B,47B 'bug':29B 'compon':34B 'contain':56B 'content':44B 'could':48B 'desktop':21B 'desktop-brows':20B 'escap':38B 'firefox':23B,31B 'free':28B 'get':49B 'ipc':33B 'meant':54B 'past':50B 'restrict':53B 'run':43B 'sandbox':37B,52B 'use':26B 'use-after-fre':25B","search_c":"'115.45':78C '153.7':82C '160':75C 'compon':68C 'due':59C 'escap':58C 'esr':77C,81C 'firefox':74C,76C,80C 'fix':72C 'free':64C 'ipc':67C 'sandbox':57C 'use':62C 'use-after-fre':61C 'vulner':70C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-10T14:17:23+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-124903","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-124903","severity":null,"published_at":"2026-11-10T14:17:23+00:00","modified_at":"2026-11-10T14:17:23+00:00","first_seen_at":"2026-11-10T14:22:17+00:00","fetched_at":"2026-11-10T14:22:17+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"}