CVE-2021-21166 — Google Chromium

Google Chromium Race Condition Vulnerability

Added to KEV

2021-11-03

Federal due date

2021-11-17

Vendor

Google

Product

Chromium

EPSS

97.3th percentile (score 0.380, as of 2026-06-08)

NVD CVSS v3.1

—

Ransomware use

Unknown

Upstream

https://nvd.nist.gov/vuln/detail/CVE-2021-21166

CISA short description

Google Chromium contains a race condition vulnerability that allows a remote attacker to potentially exploit heap corruption 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.

Required action

Apply updates per vendor instructions.

EPSS percentile is the FIRST.org exploit-probability ranking as of the date noted above; it moves daily. CVSS reflects NVD's analysis at time of publication.