CVE-2021-21220

HighPublished

Google Chromium V8 Improper Input Validation Vulnerability

Published: Apr 26, 2021
Updated: Oct 21, 2025
Assigning CNA: Chrome
Evidence observed: Nov 3, 2021

Primary CVSS

8.8/ 10High

nvd · CVSS 3.1

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS probability estimate

70.4%

High · next 30 days

Percentile: 99.4%
Model date: Oct 19, 2026

EPSS is a statistical estimate, not a certainty or a measure of impact. Combine it with CVSS, KEV status, exposure and your environment.

CISA Known Exploited

This CVE appears in the CISA Known Exploited Vulnerabilities catalog.

Summary

Insufficient validation of untrusted input in V8 in Google Chrome prior to 89.0.4389.128 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.

Sources

Repository evidence: Files: 1 · Repositories: 1

1 Module

Google Chrome versions before 89.0.4389.128 V8 XOR Typer Out-Of-Bounds Access RCEModule
modules/exploits/multi/browser/chrome_cve_2021_21220_v8_insufficient_validation.rb
Metasploit Framework modules
ExploitEvidence observed: Sep 26, 2026Revision: 1e321cedaf4cRelated tool
Declared conditions
- platform: Linux,OSX,Windows($.exploit_multi/browser/chrome_cve_2021_21220_v8_insufficient_validation.platform)
- verification: check_not_declared($.exploit_multi/browser/chrome_cve_2021_21220_v8_insufficient_validation.check)

CVE-2021-21220Research
Educational presentation detailing the exploitation of CVE-2021-21220, a V8 JIT type confusion leading to OOB access and RCE via WebAssembly, with mitigation analysis.
CVE-2021-21220

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