{"id":"CVE-2026-124931","kind":"vulnerability","aliases":["CVE-2026-124931"],"related":[],"title":"Firefox: DOM flaw lets pages bypass the same-origin policy","description":"Same-origin policy bypass in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 160 and Firefox ESR 153.7.","summary":"A flaw in the Core and HTML DOM component of Firefox lets a web page bypass the same-origin policy that keeps sites from reading each other's data. An attacker who gets a victim to visit a malicious page could read or act on data from other sites the victim is logged into.","severity":"high","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["browsers","desktop","firefox","runtime"],"not_affected_if":["patched-version"],"how_to_check":"- Open the Firefox menu, go to Settings > General > About Firefox, and read the version shown.\n- Check the installed version with `firefox --version` on Linux or macOS.","fix":"- Firefox: move to `160` or later.\n- Firefox ESR: move to `153.7` or later.","status":"open","published_at":"2026-11-10T14:17:27+00:00","first_seen_at":"2026-11-10T14:22:18+00:00","triaged_at":"2026-11-10T14:24:17+00:00","updated_at":"2026-11-10T14:24:17+00:00","category":"runtime","confidence":0.6,"triage":{"at":"2026-11-10T14:24:17Z","model":"claude-haiku-5-5","output":{"fix":"- Firefox: move to `160` or later.\n- Firefox ESR: move to `153.7` or later.","reach":"internet","title":"Firefox: DOM flaw lets pages bypass the same-origin policy","impact":"medium","summary":"A flaw in the Core and HTML DOM component of Firefox lets a web page bypass the same-origin policy that keeps sites from reading each other's data. An attacker who gets a victim to visit a malicious page could read or act on data from other sites the victim is logged into.","audience":"everyone","category":"runtime","nicknames":[],"who_cares":["firefox","browsers","desktop"],"confidence":0.6,"fix_status":"available","needs_auth":"no","worst_case":"malicious page reads data from other logged-in sites","analyst_note":"","how_to_check":"- Open the Firefox menu, go to Settings > General > About Firefox, and read the version shown.\n- Check the installed version with `firefox --version` on Linux or macOS.","plain_action":"Update Firefox to version 160 or Firefox ESR to 153.7 or later: open the Firefox menu, then Settings > General > About Firefox, and let it install.","product_name":"","needs_analyst":false,"not_affected_if":["patched-version"],"who_is_affected":"Anyone running Firefox or Firefox ESR older than the fixed versions is exposed when browsing the web. Systems where Firefox is not installed, or runs a patched build, can skip it.","user_interaction":"yes","product_ecosystem":"","needs_special_setup":"no","severity_if_unknown":"high"},"cost_usd":0.000724,"input_tokens":4486,"output_tokens":550,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-124931':14A,17A '-2026':13A,16A '153.7':97C '160':93C 'act':66B 'attack':53B 'browser':18B 'bypass':6A,37B,80C 'compon':30B,86C 'core':26B,84C 'could':63B 'cve':12A,15A 'data':51B,68B 'desktop':19B 'dom':2A,29B,83C 'esr':96C 'firefox':1A,20B,32B,92C,95C 'fix':90C 'flaw':3A,23B 'get':55B 'html':28B,85C 'keep':44B 'let':4A,33B 'log':75B 'malici':61B 'origin':10A,41B,78C 'page':5A,36B,62B 'polici':11A,42B,79C 'read':47B,64B 'runtim':21B 'same-origin':8A,39B,76C 'site':45B,71B 'victim':57B,73B 'visit':59B 'vulner':88C 'web':35B","nicknames":[],"mitigations":[],"who_affected":"Anyone running Firefox or Firefox ESR older than the fixed versions is exposed when browsing the web. Systems where Firefox is not installed, or runs a patched build, can skip it.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"everyone","plain_action":"Update Firefox to version 160 or Firefox ESR to 153.7 or later: open the Firefox menu, then Settings > General > About Firefox, and let it install.","pkeys":[],"ptokens":[],"labels":["browsers","desktop","firefox","high","runtime"],"campaign_type":null,"search_a":"'-124931':14A,17A '-2026':13A,16A 'bypass':6A 'cve':12A,15A 'dom':2A 'firefox':1A 'flaw':3A 'let':4A 'origin':10A 'page':5A 'polici':11A 'same-origin':8A","search_b":"'act':66B 'attack':53B 'browser':18B 'bypass':37B 'compon':30B 'core':26B 'could':63B 'data':51B,68B 'desktop':19B 'dom':29B 'firefox':20B,32B 'flaw':23B 'get':55B 'html':28B 'keep':44B 'let':33B 'log':75B 'malici':61B 'origin':41B 'page':36B,62B 'polici':42B 'read':47B,64B 'runtim':21B 'same-origin':39B 'site':45B,71B 'victim':57B,73B 'visit':59B 'web':35B","search_c":"'153.7':97C '160':93C 'bypass':80C 'compon':86C 'core':84C 'dom':83C 'esr':96C 'firefox':92C,95C 'fix':90C 'html':85C 'origin':78C 'polici':79C 'same-origin':76C 'vulner':88C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-10T14:17:27+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-124931","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-124931","severity":null,"published_at":"2026-11-10T14:17:27+00:00","modified_at":"2026-11-10T14:17:27+00:00","first_seen_at":"2026-11-10T14:22:18+00:00","fetched_at":"2026-11-10T14:22:18+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"}