A CWE-306: Missing Authentication for Critical Function vulnerability exists in the Web Server on Modicon M340, Legacy Offers Modicon Quantum and Modicon Premium and associated Communication Modules (see security notification for affected versions), that could cause unauthenticated command execution in the controller when sending special HTTP requests.
https://www.se.com/ww/en/download/document/SEVD-2020-343-04/