CVE-2021-21166
Exploited in the Wild
✓ Confirmed 0-Day
★ Google Project Zero
Triaged: March 5, 2026
22 articles
EPSS Score
Source: FIRST.org · 2026-05-24
37.98%
probability
This CVE has a 37.98% probability
of being exploited in the next 30 days.
0%
Top 97.3th percentile of all CVEs
100%
CVSS score unavailable
Neither CIRCL nor NVD returned a CVSS score for this CVE.
View on VulnerabilityLookup ↗
Description
Project ZeroObject lifecycle issue in audio
Google Project Zero
Discovered
Feb. 11, 2021
Patched
March 2, 2021
Reported by
Alison Huffman, Microsoft Browser Vulnerability Research & Clement Lecigne of Google Threat Analysis Group
Root Cause Analysis
https://googleprojectzero.github.io/0days-in-the-wild/0day-RCAs/2021/CVE-2021-21166.html
Google fixes second actively exploited Chrome zero-day this month
BleepingComputer
Mar 12, 2021
Google pushes emergency Chrome update to fix zero-day used in attacks
BleepingComputer
Dec 13, 2021
Emergency Google Chrome update fixes zero-days used in attacks
BleepingComputer
Oct 28, 2021
Google patches 8th Chrome zero-day exploited in the wild this year
BleepingComputer
Jul 16, 2021
Google fixes second actively exploited Chrome zero-day bug this year
BleepingComputer
Mar 02, 2021
Google pushes emergency Chrome update to fix two zero-days
BleepingComputer
Sep 30, 2021
Google: Russian SVR hackers targeted LinkedIn users with Safari zero-day
BleepingComputer
Jul 14, 2021
Google Chrome emergency update fixes zero-day exploited in attacks
BleepingComputer
Feb 14, 2022
Microsoft March 2021 Patch Tuesday fixes 82 flaws, 2 zero-days
BleepingComputer
Mar 09, 2021
Emergency Google Chrome update fixes zero-day exploited in the wild
BleepingComputer
Sep 24, 2021
Google patches 10th Chrome zero-day exploited in the wild this year
BleepingComputer
Sep 13, 2021
Google fixes seventh Chrome zero-day exploited in the wild this year
BleepingComputer
Jun 17, 2021
Google fixes sixth Chrome zero-day exploited in the wild this year
BleepingComputer
Jun 09, 2021
Signal Intelligence
Confidence
95%
EPSS
37.98%
Mentions
22
Last Seen
Feb 14, 2022
CNA Information
Analyst Note
Auto-imported from Google Project Zero — confirmed zero-day by definition.
Threat Actors 1
Infy
apt_group
Information theft and espionage
🇮🇷 IR
Triage Info
Decided atMar 05, 2026