A CWE-787: Out-of-bounds Write vulnerability exists in the Web Server on Modicon M340, Modicon Quantum and Modicon Premium Legacy offers and their Communication Modules (see notification for details) which could cause corruption of data, a crash, or code execution when uploading a specially crafted file on the controller over FTP.
https://www.se.com/ww/en/download/document/SEVD-2020-315-01/