CVE-2021-36798: Helpsystems Cobalt Strike

High severity, CVSS 7.5. EPSS: 4.3% chance of exploitation in the next 30 days.

A Denial-of-Service (DoS) vulnerability was discovered in Team Server in HelpSystems Cobalt Strike 4.2 and 4.3. It allows remote attackers to crash the C2 server thread and block beacons' communication with it.

Affected products

• Helpsystems Cobalt Strike: version 4.2 only; version 4.3 only

Published 2021-08-09. Last modified 2026-06-17.