{"id":"CVE-2021-21193","kind":"vulnerability","aliases":["CVE-2021-21193"],"related":[],"title":"Google Chromium Blink: Google Chromium Blink Use-After-Free Vulnerability","description":"Google Chromium Blink contains a use-after-free vulnerability that allows a remote attacker to potentially exploit heap corruption via a crafted HTML page. This vulnerability could affect multiple web browsers that utilize Chromium, including, but not limited to, Google Chrome, Microsoft Edge, and Opera.\n\nCISA required action: Apply updates per vendor instructions.","summary":"A use-after-free bug in Chromium's Blink rendering engine lets a remote attacker corrupt heap memory by serving a crafted HTML page. Chromium-based browsers such as Chrome, Edge and Opera are affected, and CISA lists it as exploited in the wild.","severity":"high","cvss":8.8,"epss":0.0995,"exploited":true,"exploited_at":"2021-11-03T00:00:00+00:00","products":[{"name":"Google Chromium Blink","fixed":[],"affected":"","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["browsers","chrome","chromium","edge","exploited","opera","other"],"not_affected_if":["fully-patched-browser"],"how_to_check":"Open the browser's version page (chrome://version or edge://version) and compare against the fixed version.","fix":"Update the browser to a Chromium release that includes the vendor's fix for CVE-2021-21193, per vendor instructions.","status":"open","published_at":"2021-03-16T15:15:13+00:00","first_seen_at":"2026-10-23T19:11:53+00:00","triaged_at":"2026-10-23T21:39:25+00:00","updated_at":"2026-10-23T21:57:35+00:00","category":"other","confidence":0.6,"triage":{"at":"2026-10-23T21:39:25Z","model":"claude-haiku-5-5","output":{"fix":"Update the browser to a Chromium release that includes the vendor's fix for CVE-2021-21193, per vendor instructions.\nunknown","reach":"internet","impact":"high","summary":"A use-after-free bug in Chromium's Blink rendering engine lets a remote attacker corrupt heap memory by serving a crafted HTML page. Chromium-based browsers such as Chrome, Edge and Opera are affected, and CISA lists it as exploited in the wild.","category":"other","who_cares":["chrome","edge","opera","chromium","browsers"],"confidence":0.6,"needs_auth":"no","worst_case":"Attacker runs code in the browser via a malicious web page.","analyst_note":"Find the fixed Chromium version and release date for CVE-2021-21193 in the Chrome Releases blog or NVD, since the sources here give no version.","how_to_check":"Open the browser's version page (chrome://version or edge://version) and compare against the fixed version.\nunknown\nunknown","needs_analyst":true,"not_affected_if":["fully-patched-browser"],"user_interaction":"yes","needs_special_setup":"no","severity_if_unknown":"high"},"cost_usd":0.000493,"input_tokens":2887,"output_tokens":409,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2021':13A,16A '-21193':14A,17A 'action':121C 'affect':63B,101C 'allow':84C 'appli':122C 'attack':42B,87C 'base':54B 'blink':3A,6A,20A,36B,75C 'browser':21B,55B,104C 'bug':32B 'chrome':22B,58B,114C 'chromium':2A,5A,19A,23B,34B,53B,74C,107C 'chromium-bas':52B 'cisa':65B,119C 'contain':76C 'corrupt':43B,92C 'could':100C 'craft':49B,95C 'cve':12A,15A 'edg':24B,59B,116C 'engin':38B 'exploit':25B,69B,90C 'free':10A,31B,81C 'googl':1A,4A,73C,113C 'google':18A 'heap':44B,91C 'html':50B,96C 'includ':108C 'instruct':126C 'let':39B 'limit':111C 'list':66B 'memori':45B 'microsoft':115C 'multipl':102C 'opera':26B,61B,118C 'page':51B,97C 'per':124C 'potenti':89C 'remot':41B,86C 'render':37B 'requir':120C 'serv':47B 'updat':123C 'use':8A,29B,79C 'use-after-fre':7A,28B,78C 'util':106C 'vendor':125C 'via':93C 'vulner':11A,82C,99C 'web':103C 'wild':72B","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2021-03-16T15:15:13+00:00","kev":{"dateAdded":"2021-11-03","dueDate":"2021-11-17","requiredAction":"Apply updates per vendor instructions.","knownRansomwareCampaignUse":"Unknown"},"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","cvss_by":"nvd@nist.gov","poc_count":0,"sources":[{"source":"kev","external_id":"CVE-2021-21193","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-21193","severity":null,"published_at":"2021-11-03T00:00:00+00:00","modified_at":null,"first_seen_at":"2026-10-23T19:11:53+00:00","fetched_at":"2026-10-25T20:35:38+00:00","note":null},{"source":"epss","external_id":"CVE-2021-21193","url":"https://api.first.org/data/v1/epss?cve=CVE-2021-21193","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-23T19:13:44+00:00","fetched_at":"2026-10-23T19:13:44+00:00","note":null},{"source":"nvd","external_id":"CVE-2021-21193","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-21193","severity":null,"published_at":"2021-03-16T15:15:13+00:00","modified_at":"2026-06-17T03:35:00+00:00","first_seen_at":"2026-10-23T21:57:35+00:00","fetched_at":"2026-10-23T21:57:35+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"}