# CVE-2021-21220: Google Chromium V8 Improper Input Validation Vulnerability

Source: https://junglewise.ai/threats/cve-2021-21220-google-chromium-v8-improper-input-validation-vulnerability  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2021-11-03. Updated: 2026-05-10  
License: CC BY 4.0 with a link back

CVE-2021-21220 · Severity: critical · CVSS 8.8 · Exploited in the wild · Published 2021-11-03

Google Chromium V8 Engine contains an improper input validation vulnerability that allows a remote attacker to potentially exploit heap corruption via a crafted HTML page. This flaw can lead to arbitrary code execution within the context of the browser process.

Technologies: [Google Chromium V8](https://junglewise.ai/threats/technologies/chromium-v8). Vendors: [Google](https://junglewise.ai/threats/vendors/google).

## Quick answers

**Is CVE-2021-21220 exploited in the wild?** Yes. CVE-2021-21220 is known to be exploited in the wild, first recorded on 3 November 2021. Treat it as urgent.

**How severe is CVE-2021-21220?** Critical severity, with a CVSS score of 8.8, published 3 November 2021.

**Which products and versions are affected?** Google Chrome prior to 89.0.4389.128; Google V8 prior to 89.0.4389.128; Microsoft Edge; Opera Software Opera.

**Is there a fix for CVE-2021-21220?** A patch was published on 2021-04-13: Stable Channel Update for Desktop 89.0.4389.128 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2021-21220 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2021-21220?** Check whether you run Google Chromium V8. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Affected products

- Google Chrome prior to 89.0.4389.128
- Google V8 prior to 89.0.4389.128
- Microsoft Edge
- Opera Software Opera

## Timeline

- 2021-04-13: patched: Stable Channel Update for Desktop 89.0.4389.128
- 2021-11-03: disclosed: Published in NVD
- 2021-11-03: kev added: Added to CISA Known Exploited Vulnerabilities Catalog
- 2021-11-03: exploited: Confirmed exploited in the wild per CISA KEV catalog entry date.

## Related threats

- [Google Chromium V8 out-of-bounds write in JavaScript engine](https://junglewise.ai/threats/cve-2026-87491-google-chromium-v8-out-of-bounds-write-in-javascript-engine)
- [Google Chromium V8 type confusion vulnerability](https://junglewise.ai/threats/cve-2026-85046-google-chromium-v8-type-confusion-vulnerability)
- [Google Chrome V8 out of bounds read and write](https://junglewise.ai/threats/cve-2026-11645-google-chrome-v8-out-of-bounds-read-and-write)
- [Google Chromium V8 memory corruption in JavaScript engine](https://junglewise.ai/threats/cve-2026-3910-google-chromium-v8-memory-corruption-in-javascript-engine)
- [Google Chrome type confusion in V8 engine](https://junglewise.ai/threats/cve-2025-13223-google-chrome-type-confusion-in-v8-engine)