Hazard

Is CVE-2021-26411 being exploited?

Ransomware crews are using this

CISA has linked this vulnerability to known ransomware campaigns. Treat any exposed instance as an active incident, not a patching ticket.

Microsoft Internet Explorer Memory Corruption Vulnerability

Microsoft · Internet Explorer

CVSS 8.8 EPSS 81% no public exploit indexed ransomware Fix deadline passed 17 November 2021

What it is

Microsoft Internet Explorer contains an unspecified vulnerability that allows for memory corruption.

Why we say that

  • Linked by CISA to known ransomware campaigns
  • EPSS puts exploitation in the next 30 days at 81%
  • CISA's federal remediation deadline (2021-11-17) 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. This vulnerability is used in ransomware campaigns; here is what ransomware has cost UK organisations at the regulator.

All UK cases caused by ransomware →