{"id":"CVE-2021-30633","kind":"vulnerability","aliases":["CVE-2021-30633"],"related":[],"title":"Google Chromium Indexed DB API: Google Chromium Indexed DB API Use-After-Free Vulnerability","description":"Google Chromium Indexed DB API contains a use-after-free vulnerability that allows a remote attacker, who has compromised the renderer process, to potentially perform a sandbox escape 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 the Chromium Indexed DB API lets a remote attacker who already controls the browser renderer escape the sandbox via a crafted HTML page. It is listed as actively exploited in the wild by CISA.","severity":"critical","cvss":9.6,"epss":0.3318,"exploited":true,"exploited_at":"2021-11-03T00:00:00+00:00","products":[{"name":"Google Chromium Indexed DB API","fixed":[],"affected":"","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["browsers","chrome","chromium","edge","exploited","opera","vendor"],"not_affected_if":["patched-browser-build"],"how_to_check":"Check the installed browser version (for example chrome://version in Chrome or edge://version in Edge) and compare it to the fixed release named by the vendor.","fix":"Update Chrome, Edge, Opera or any other Chromium-based browser to a build released after the 2021 Chromium fix, per vendor instructions.","status":"open","published_at":"2021-10-08T21:15:07+00:00","first_seen_at":"2026-10-23T19:11:53+00:00","triaged_at":"2026-10-23T21:39:24+00:00","updated_at":"2026-10-23T21:57:35+00:00","category":"vendor","confidence":0.6,"triage":{"at":"2026-10-23T21:39:24Z","model":"claude-haiku-5-5","output":{"fix":"Update Chrome, Edge, Opera or any other Chromium-based browser to a build released after the 2021 Chromium fix, per vendor instructions.\nunknown","reach":"internet","impact":"high","summary":"A use-after-free bug in the Chromium Indexed DB API lets a remote attacker who already controls the browser renderer escape the sandbox via a crafted HTML page. It is listed as actively exploited in the wild by CISA.","category":"vendor","who_cares":["chromium","chrome","edge","opera","browsers"],"confidence":0.6,"needs_auth":"no","worst_case":"Attacker escapes renderer sandbox and runs code on the user's machine.","analyst_note":"Fixed version numbers are not in the sources; check the Chrome Releases blog or the NVD entry for CVE-2021-30633 for the first patched build.","how_to_check":"Check the installed browser version (for example chrome://version in Chrome or edge://version in Edge) and compare it to the fixed release named by the vendor.\nunknown\nunknown","needs_analyst":true,"not_affected_if":["patched-browser-build"],"user_interaction":"yes","needs_special_setup":"no","severity_if_unknown":"high"},"cost_usd":0.000505,"input_tokens":2916,"output_tokens":426,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2021':17A,20A '-30633':18A,21A 'action':132C 'activ':68B 'affect':112C 'allow':88C 'alreadi':51B 'api':5A,10A,26A,45B,79C 'appli':133C 'attack':49B,91C 'browser':27B,54B,115C 'bug':39B 'chrome':28B,125C 'chromium':2A,7A,23A,29B,42B,76C,118C 'cisa':74B,130C 'compromis':94C 'contain':80C 'control':52B 'could':111C 'craft':61B,106C 'cve':16A,19A 'db':4A,9A,25A,44B,78C 'edg':30B,127C 'escap':56B,103C 'exploit':31B,69B 'free':14A,38B,85C 'googl':1A,6A,75C,124C 'google':22A 'html':62B,107C 'includ':119C 'index':3A,8A,43B,77C 'indexed':24A 'instruct':137C 'let':46B 'limit':122C 'list':66B 'microsoft':126C 'multipl':113C 'opera':32B,129C 'page':63B,108C 'per':135C 'perform':100C 'potenti':99C 'process':97C 'remot':48B,90C 'render':55B,96C 'requir':131C 'sandbox':58B,102C 'updat':134C 'use':12A,36B,83C 'use-after-fre':11A,35B,82C 'util':117C 'vendor':33B,136C 'via':59B,104C 'vulner':15A,86C,110C 'web':114C 'wild':72B","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2021-10-08T21:15:07+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:C/C:H/I:H/A:H","cvss_by":"nvd@nist.gov","poc_count":0,"sources":[{"source":"kev","external_id":"CVE-2021-30633","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-30633","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":"2026-10-25T12:39:25+00:00","note":null},{"source":"epss","external_id":"CVE-2021-30633","url":"https://api.first.org/data/v1/epss?cve=CVE-2021-30633","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-2021-30633","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-30633","severity":null,"published_at":"2021-10-08T21:15:07+00:00","modified_at":"2026-06-17T03:50:36+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"}