CVE-2021-21224Known exploitationNetwork attack vector

Arbitrary code execution via V8 type confusion

Published Apr 26, 2021 · Updated Oct 21, 2025

Type confusion in V8 in Google Chrome before 90.0.4430.85 allows remote attackers to execute arbitrary code in the sandbox via crafted HTML. Google's public record identifies only V8 type confusion and does not disclose the affected function or incompatible-type operation. Exploitation requires a user to load attacker-controlled HTML; successful code execution remains confined to the browser sandbox.

CVSS severity8.8
High
EPSS probability84.17%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Type confusion in V8 in Google Chrome before 90.0.4430.85 allows remote attackers to execute arbitrary code in the sandbox via crafted HTML. Google's public record identifies only V8 type confusion and does not disclose the affected function or incompatible-type operation. Exploitation requires a user to load attacker-controlled HTML; successful code execution remains confined to the browser sandbox.

The record

CVE
CVE-2021-21224
Published
Apr 26, 2021
Updated
Oct 21, 2025
Vendor
Google Cloud
Product
Google Chrome
Classifications
CWE-843, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 20, 2021Exploitation reportedGoogle reports in-the-wild exploitation
  2. Apr 26, 2021CVE publishedPublication date reported by the CVE source.
  3. Oct 21, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <90.0.4430.85

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Google Cloud · Google Chromeversion=unspecified <90.0.4430.85

Published CVSS scores

8.8National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
6.8National Vulnerability DatabaseAV:N/AC:M/Au:N/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-843Access of Resource Using Incompatible Type ('Type Confusion')
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

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Your stack

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