Hazard

Is CVE-2021-4102 being exploited?

Confirmed exploited in the wild

CISA has evidence of active exploitation. This is not theoretical risk — someone has already used it against someone.

Google Chromium V8 Use-After-Free Vulnerability

Google · Chromium V8

CVSS 8.8 EPSS 8% no public exploit indexed Fix deadline passed 29 December 2021

What it is

Google Chromium V8 Engine contains a use-after-free 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.

Why we say that

  • CISA's federal remediation deadline (2021-12-29) has passed
  • Listed in the CISA Known Exploited Vulnerabilities catalogue

Every line above comes from a named public source. Where the evidence is thin, we say so rather than inventing confidence — see methodology.

What to do

Apply updates per vendor instructions.

What it costs when this goes wrong

This is where UK enforcement meets the vulnerability record. Where an unfixed vulnerability leads to a breach, the ICO treats it as a security failure under UK GDPR. Recent cases:

All UK cases caused by unpatched software →