---
id: "CVE-2021-30633"
kind: "vulnerability"
aliases: ["CVE-2021-30633"]
title: "Google Chromium Indexed DB API: Google Chromium Indexed DB API Use-After-Free Vulnerability"
severity: "critical"
cvss: 9.6
epss: 0.3318
exploited: true
status: "open"
category: "vendor"
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"]
published_at: "2021-10-08T21:15:07+00:00"
first_seen_at: "2026-10-23T19:11:53+00:00"
updated_at: "2026-10-23T21:57:35+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-30633", "first_seen_at": "2026-10-23T19:11:53+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2021-30633", "first_seen_at": "2026-10-23T19:13:44+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-30633", "first_seen_at": "2026-10-23T21:57:35+00:00"}]
---

# Google Chromium Indexed DB API: Google Chromium Indexed DB API Use-After-Free Vulnerability

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.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Google Chromium Indexed DB API affected ? fixed ?

## 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.

## Timeline

- 2026-10-23T19:11:53+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-30633
- 2026-10-23T19:13:44+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2021-30633
- 2026-10-23T21:57:35+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2021-30633

## From the sources

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.

CISA required action: Apply updates per vendor instructions.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_