{"id":"CVE-2026-121108","kind":"vulnerability","aliases":["CVE-2026-121108"],"related":[],"title":"Chrome: BackgroundFetch confused deputy lets a web page bypass origin policy","description":"Confused deputy in BackgroundFetch in Google Chrome prior to 157.0.8103.38 allowed a remote attacker to potentially bypass web origin policy via a crafted HTML page. (Chromium security severity: Medium)","summary":"Google Chrome versions before 157.0.8103.38 have a confused deputy flaw in the BackgroundFetch feature. A remote attacker can use a crafted HTML page to potentially bypass web origin policy.","severity":"medium","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["browsers","chrome","package","web"],"not_affected_if":["chromium-version-current"],"how_to_check":"- Check the installed Chrome version in Chrome's About page (chrome://settings/help)\n- Compare the installed version against `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":"package","confidence":0.7,"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: BackgroundFetch confused deputy lets a web page bypass origin policy","impact":"medium","summary":"Google Chrome versions before 157.0.8103.38 have a confused deputy flaw in the BackgroundFetch feature. A remote attacker can use a crafted HTML page to potentially bypass web origin policy.","audience":"everyone","category":"package","nicknames":[],"who_cares":["chrome","browsers","web"],"confidence":0.7,"fix_status":"available","needs_auth":"no","worst_case":"A crafted web page bypasses origin restrictions and reads cross-site data","analyst_note":"","how_to_check":"- Check the installed Chrome version in Chrome's About page (chrome://settings/help)\n- Compare the installed version against `157.0.8103.38`","plain_action":"Update Google Chrome to version 157.0.8103.38 or later.","needs_analyst":false,"not_affected_if":["chromium-version-current"],"who_is_affected":"Anyone running Google Chrome before 157.0.8103.38 who visits web pages, including untrusted ones. Exposure comes from the browser itself, not from a server-side configuration. Teams that manage browsers on employee machines should check versions there.","user_interaction":"yes","needs_special_setup":"no","severity_if_unknown":"medium"},"cost_usd":0.00066,"input_tokens":4108,"output_tokens":498,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-121108':14A,17A '-2026':13A,16A '157.0.8103.38':26B,60C 'allow':61C 'attack':38B,64C 'backgroundfetch':2A,34B,54C 'browser':18B 'bypass':9A,47B,67C 'chrome':1A,19B,23B,57C 'chromium':76C 'confus':3A,29B,51C 'craft':42B,73C 'cve':12A,15A 'deputi':4A,30B,52C 'featur':35B 'flaw':31B 'googl':22B,56C 'html':43B,74C 'let':5A 'medium':79C 'origin':10A,49B,69C 'packag':20B 'page':8A,44B,75C 'polici':11A,50B,70C 'potenti':46B,66C 'prior':58C 'remot':37B,63C 'secur':77C 'sever':78C 'use':40B 'version':24B 'via':71C 'web':7A,21B,48B,68C","nicknames":[],"mitigations":[],"who_affected":"Anyone running Google Chrome before 157.0.8103.38 who visits web pages, including untrusted ones. Exposure comes from the browser itself, not from a server-side configuration. Teams that manage browsers on employee machines should check versions there.","tier":"C","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","medium","package","web"],"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-2026-121108","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-121108","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"}