{"id":"CVE-2026-121107","kind":"vulnerability","aliases":["CVE-2026-121107"],"related":[],"title":"Chrome: background fetch authorization flaw lets a web page bypass origin policy","description":"Incorrect authorization in BackgroundFetch in Google Chrome prior to 157.0.8103.38 allowed a remote attacker to bypass web origin policy via a crafted HTML page. (Chromium security severity: High)","summary":"Google Chrome versions before 157.0.8103.38 have an incorrect authorization check in BackgroundFetch. A remote attacker can use a crafted HTML page to bypass web origin policy.","severity":"high","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["browsers","chrome","end-users","other"],"not_affected_if":["chrome-updated"],"how_to_check":"- Check the Chrome version in the browser's About page or with `chrome://version`.\n- Confirm whether the installed version is below `157.0.8103.38`.","fix":"- Google Chrome: move to `157.0.8103.38` or later.","status":"open","published_at":"2026-11-03T21:17:17+00:00","first_seen_at":"2026-11-03T21:19:15+00:00","triaged_at":"2026-11-03T21:25:12+00:00","updated_at":"2026-11-03T21:25:12+00:00","category":"other","confidence":0.6,"triage":{"at":"2026-11-03T21:25:12Z","model":"claude-haiku-5-5","output":{"fix":"- Google Chrome: move to `157.0.8103.38` or later.","reach":"internet","title":"Chrome: background fetch authorization flaw lets a web page bypass origin policy","impact":"medium","summary":"Google Chrome versions before 157.0.8103.38 have an incorrect authorization check in BackgroundFetch. A remote attacker can use a crafted HTML page to bypass web origin policy.","audience":"everyone","category":"other","nicknames":[],"who_cares":["chrome","browsers","end-users"],"confidence":0.6,"fix_status":"available","needs_auth":"no","worst_case":"A malicious web page bypasses origin restrictions in the browser.","analyst_note":"","how_to_check":"- Check the Chrome version in the browser's About page or with `chrome://version`.\n- Confirm whether the installed version is below `157.0.8103.38`.","plain_action":"Update Google Chrome to version 157.0.8103.38 or later.","needs_analyst":false,"not_affected_if":["chrome-updated"],"who_is_affected":"Anyone running Google Chrome older than 157.0.8103.38 who visits a web page that could be crafted by an attacker. Managed fleets should check browser versions centrally. Users on the latest Chrome build are not affected.","user_interaction":"yes","needs_special_setup":"no","severity_if_unknown":"high"},"cost_usd":0.000651,"input_tokens":4104,"output_tokens":482,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-121107':15A,18A '-2026':14A,17A '157.0.8103.38':28B,59C 'allow':60C 'attack':38B,63C 'author':4A,32B,51C 'background':2A 'backgroundfetch':35B,53C 'browser':19B 'bypass':10A,46B,65C 'check':33B 'chrome':1A,20B,25B,56C 'chromium':74C 'craft':42B,71C 'cve':13A,16A 'end':22B 'end-us':21B 'fetch':3A 'flaw':5A 'googl':24B,55C 'high':77C 'html':43B,72C 'incorrect':31B,50C 'let':6A 'origin':11A,48B,67C 'page':9A,44B,73C 'polici':12A,49B,68C 'prior':57C 'remot':37B,62C 'secur':75C 'sever':76C 'use':40B 'user':23B 'version':26B 'via':69C 'web':8A,47B,66C","nicknames":[],"mitigations":[],"who_affected":"Anyone running Google Chrome older than 157.0.8103.38 who visits a web page that could be crafted by an attacker. Managed fleets should check browser versions centrally. Users on the latest Chrome build are not affected.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"everyone","plain_action":"Update Google Chrome to version 157.0.8103.38 or later.","pkeys":[],"ptokens":[],"labels":["browsers","chrome","endusers","high","other"],"campaign_type":null,"first_public_at":"2026-11-03T21:17:17+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-121107","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-121107","severity":null,"published_at":"2026-11-03T21:17:17+00:00","modified_at":"2026-11-03T21:17:17+00:00","first_seen_at":"2026-11-03T21:19:15+00:00","fetched_at":"2026-11-03T21:19:15+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"}