CVE-2021-21187
✓ Confirmed 0-Day
Triaged: March 20, 2026
2 articles
EPSS Score
Source: FIRST.org · 2026-05-24
0.93%
probability
This CVE has a 0.93% probability
of being exploited in the next 30 days.
0%
Top 76.3th percentile of all CVEs
100%
CVSS score unavailable
Neither CIRCL nor NVD returned a CVSS score for this CVE.
View on VulnerabilityLookup ↗
Google fixes second actively exploited Chrome zero-day bug this year
BleepingComputer
Mar 02, 2021
Microsoft March 2021 Patch Tuesday fixes 82 flaws, 2 zero-days
BleepingComputer
Mar 09, 2021
Signal Intelligence
Confidence
85%
EPSS
0.93%
Mentions
2
Last Seen
Mar 09, 2021
CNA Information
Analyst Note
CVE-2021-21187 is explicitly named as an actively exploited Chrome zero-day in a BleepingComputer article from 2021. The title directly states 'Google fixes second actively exploited Chrome zero-day bug this year,' indicating exploitation occurred before or concurrent with the patch. This meets the zero-day criteria of wild exploitation prior to patch availability.
Triage Info
Decided atMar 20, 2026