CVE-2021-21223

ENISA EUVD: EUVD-2021-8614 ↗
✓ Confirmed 0-Day
Triaged: March 20, 2026 1 article Published: 2021-04-26
VulnLookup ↗ NVD ↗ EUVD ↗ MITRE ↗

EPSS Score

Source: FIRST.org · 2026-05-23
1.16%
probability
This CVE has a 1.16% probability of being exploited in the next 30 days.
0% Top 78.8th percentile of all CVEs 100%

CVSS v3.1

Source: NVD
9.6
CRITICAL
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

CVSS v2 (legacy)

6.8
MEDIUM
Access Vector
Network
Access Complexity
Medium
Authentication
None
Confidentiality
Partial
Integrity
Partial
Availability
Partial
AV:N/AC:M/Au:N/C:P/I:P/A:P

Description

VulnerabilityLookup (CNA)
Integer overflow in Mojo in Google Chrome prior to 90.0.4430.85 allowed a remote attacker who had compromised the renderer process to potentially perform a sandbox escape via a crafted HTML page.

Affected Products

Google
Chrome
unspecified

Attack Intelligence

Signal Intelligence

Confidenceⓘ
85%
EPSS 1.16%
CVSS v3.1 9.6
Mentions 1
Last Seen Apr 21, 2021

CNA Information

CNA Assigner
Chrome

Analyst Note

BleepingComputer article explicitly identifies CVE-2021-21223 as an 'exploited Chrome zero-day' with active exploitation occurring before patch availability (exploit 'dropped on Twitter last week' prior to Google's fix). CVE year 2021 and contemporary reporting align with zero-day exploitation criteria.

Triage Info

Decided atMar 20, 2026
Published DateApr 26, 2021