ACTIVELY EXPLOITED

CVE-2021-21166: Google Chromium Race Condition Vulnerability

Facts
VendorGoogle
ProductChromium
Actively exploitedYes
Added to CISA KEV3 Nov 2021
CISA federal deadline17 Nov 2021
Weakness (CWE)CWE-122, CWE-362

Required action (CISA's text)

Apply updates per vendor instructions.

Description (NVD)

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.

SOURCES

Other Google flaws

Data from NVD, CISA KEV, FIRST EPSS and vendor advisories. Updated 10 Nov 2026.