{"id":"CVE-2021-30551","kind":"vulnerability","aliases":["CVE-2021-30551"],"related":[],"title":"Google Chromium V8: Google Chromium V8 Type Confusion Vulnerability","description":"Google Chromium V8 Engine contains a type confusion 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 type confusion bug in the Chromium V8 JavaScript engine lets a remote attacker corrupt heap memory using a crafted HTML page. It is listed as actively exploited in the wild.","severity":"high","cvss":8.8,"epss":0.64701,"exploited":true,"exploited_at":"2021-11-03T00:00:00+00:00","products":[{"name":"Google Chromium V8","fixed":[],"affected":"","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["browsers","chrome","chromium","edge","exploited","opera","runtime"],"not_affected_if":["fully-patched-browser"],"how_to_check":"Open chrome://version (or edge://version, opera://version) and compare the Chromium version against the fixed release for CVE-2021-30551 in the vendor advisory; the sources do not give the fixed version.","fix":"Update Google Chrome, Microsoft Edge, Opera and other Chromium-based browsers to the vendor-patched release, as CISA directs.","status":"open","published_at":"2021-06-15T22:15:09+00:00","first_seen_at":"2026-10-23T19:11:53+00:00","triaged_at":"2026-10-23T21:39:39+00:00","updated_at":"2026-10-23T21:57:35+00:00","category":"runtime","confidence":0.6,"triage":{"at":"2026-10-23T21:39:39Z","model":"claude-haiku-5-5","output":{"fix":"Update Google Chrome, Microsoft Edge, Opera and other Chromium-based browsers to the vendor-patched release, as CISA directs.\nunknown","reach":"internet","impact":"high","summary":"A type confusion bug in the Chromium V8 JavaScript engine lets a remote attacker corrupt heap memory using a crafted HTML page. It is listed as actively exploited in the wild.","category":"runtime","who_cares":["chrome","edge","opera","chromium","browsers"],"confidence":0.6,"needs_auth":"no","worst_case":"Attacker runs code in the browser by luring a user to a malicious page.","analyst_note":"Find the fixed Chromium version and vendor advisory for CVE-2021-30551 (Chrome release notes from 2021) to fill in how_to_check and fix.","how_to_check":"Open chrome://version (or edge://version, opera://version) and compare the Chromium version against the fixed release for CVE-2021-30551 in the vendor advisory; the sources do not give the fixed version.\nunknown","needs_analyst":true,"not_affected_if":["fully-patched-browser"],"user_interaction":"yes","needs_special_setup":"no","severity_if_unknown":"high"},"cost_usd":0.000504,"input_tokens":2887,"output_tokens":430,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2021':11A,14A '-30551':12A,15A 'action':104C 'activ':52B 'affect':84C 'allow':67C 'appli':105C 'attack':39B,70C 'browser':19B,87C 'bug':29B 'chrome':20B,97C 'chromium':2A,5A,17A,21B,32B,58C,90C 'cisa':102C 'confus':8A,28B,64C 'contain':61C 'corrupt':40B,75C 'could':83C 'craft':45B,78C 'cve':10A,13A 'edg':22B,99C 'engin':35B,60C 'exploit':23B,53B,73C 'googl':1A,4A,57C,96C 'google':16A 'heap':41B,74C 'html':46B,79C 'includ':91C 'instruct':109C 'javascript':34B 'let':36B 'limit':94C 'list':50B 'memori':42B 'microsoft':98C 'multipl':85C 'opera':24B,101C 'page':47B,80C 'per':107C 'potenti':72C 'remot':38B,69C 'requir':103C 'runtim':25B 'type':7A,27B,63C 'updat':106C 'use':43B 'util':89C 'v8':3A,6A,18A,33B,59C 'vendor':108C 'via':76C 'vulner':9A,65C,82C 'web':86C 'wild':56B","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2021-06-15T22:15:09+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-2021-30551","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-30551","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":"2026-10-25T13:39:33+00:00","note":null},{"source":"epss","external_id":"CVE-2021-30551","url":"https://api.first.org/data/v1/epss?cve=CVE-2021-30551","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-2021-30551","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-30551","severity":null,"published_at":"2021-06-15T22:15:09+00:00","modified_at":"2026-06-17T03:50:26+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"}