CVE-2021-33577: Cleo Lexicom

Medium severity, CVSS 5.3. EPSS: 0.6% chance of exploitation in the next 30 days.

An issue was discovered in Cleo LexiCom 5.5.0.0. The requirement for the sender of an AS2 message to identify themselves (via encryption and signing of the message) can be bypassed by changing the Content-Type of the message to text/plain.

Affected products

• Cleo Lexicom: version 5.5.0.0 only

Published 2021-06-18. Last modified 2026-06-17.