{"id":"CVE-2026-121257","kind":"vulnerability","aliases":["CVE-2026-121257"],"related":[],"title":"Chrome: use-after-free in tab strip lets crafted extension run code","description":"Use after free in TabStrip in Google Chrome prior to 157.0.8103.38 allowed a remote attacker to potentially execute arbitrary code outside the sandbox via a crafted Chrome extension. (Chromium security severity: Medium)","summary":"A use-after-free bug in the TabStrip component of Google Chrome before 157.0.8103.38 can be triggered by a crafted Chrome extension. A remote attacker could potentially execute arbitrary code outside the browser sandbox.","severity":"medium","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["browser","chrome","desktop","other"],"not_affected_if":["chrome-updated"],"how_to_check":"- Check the Chrome version under Chrome menu > Help > About Google Chrome, or run `chrome --version` on the machine where Chrome is installed.\n- Confirm whether the installed version is below `157.0.8103.38`.","fix":"- Google Chrome: `157.0.8103.38` or later","status":"open","published_at":"2026-11-03T21:17:36+00:00","first_seen_at":"2026-11-03T21:19:30+00:00","triaged_at":"2026-11-03T21:20:52+00:00","updated_at":"2026-11-03T21:20:52+00:00","category":"other","confidence":0.6,"triage":{"at":"2026-11-03T21:20:52Z","model":"claude-haiku-5-5","output":{"fix":"- Google Chrome: `157.0.8103.38` or later","reach":"internet","title":"Chrome: use-after-free in tab strip lets crafted extension run code","impact":"high","summary":"A use-after-free bug in the TabStrip component of Google Chrome before 157.0.8103.38 can be triggered by a crafted Chrome extension. A remote attacker could potentially execute arbitrary code outside the browser sandbox.","audience":"everyone","category":"other","nicknames":[],"who_cares":["chrome","desktop","browser"],"confidence":0.6,"fix_status":"available","needs_auth":"no","worst_case":"Code runs outside the browser sandbox on the user's machine.","analyst_note":"","how_to_check":"- Check the Chrome version under Chrome menu > Help > About Google Chrome, or run `chrome --version` on the machine where Chrome is installed.\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 before 157.0.8103.38, including desktop browsers on managed or personal machines. The sources describe exploitation through a crafted Chrome extension, so exposure depends on the browser build and not on any server configuration.","user_interaction":"yes","needs_special_setup":"no","severity_if_unknown":"medium"},"cost_usd":0.00067,"input_tokens":4109,"output_tokens":518,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-121257':16A,19A '-2026':15A,18A '157.0.8103.38':37B,68C 'allow':69C 'arbitrari':52B,76C 'attack':48B,72C 'browser':20B,56B 'bug':28B 'chrome':1A,21B,35B,44B,65C,84C 'chromium':86C 'code':13A,53B,77C 'compon':32B 'could':49B 'craft':10A,43B,83C 'cve':14A,17A 'desktop':22B 'execut':51B,75C 'extens':11A,45B,85C 'free':5A,27B,60C 'googl':34B,64C 'let':9A 'medium':89C 'outsid':54B,78C 'potenti':50B,74C 'prior':66C 'remot':47B,71C 'run':12A 'sandbox':57B,80C 'secur':87C 'sever':88C 'strip':8A 'tab':7A 'tabstrip':31B,62C 'trigger':40B 'use':3A,25B,58C 'use-after-fre':2A,24B 'via':81C","nicknames":[],"mitigations":[],"who_affected":"Anyone running Google Chrome before 157.0.8103.38, including desktop browsers on managed or personal machines. The sources describe exploitation through a crafted Chrome extension, so exposure depends on the browser build and not on any server configuration.","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":["browser","chrome","desktop","medium","other"],"campaign_type":null,"first_public_at":"2026-11-03T21:17:36+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-121257","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-121257","severity":null,"published_at":"2026-11-03T21:17:36+00:00","modified_at":"2026-11-03T21:17:36+00:00","first_seen_at":"2026-11-03T21:19:30+00:00","fetched_at":"2026-11-03T21:19:30+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"}