Hazard

Is CVE-2020-5135 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.

SonicWall SonicOS Buffer Overflow Vulnerability

SonicWall · SonicOS

CVSS 9.8 EPSS 27% no public exploit indexed ransomware Fix deadline passed 5 April 2022

What it is

A buffer overflow vulnerability in SonicOS allows a remote attacker to cause Denial of Service (DoS) and potentially execute arbitrary code by sending a malicious request to the firewall.

Why we say that

  • Linked by CISA to known ransomware campaigns
  • CISA's federal remediation deadline (2022-04-05) has passed
  • CVSS 9.8 critical
  • 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 →