A CWE-125: Out-of-Bounds Read 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 a segmentation fault or a buffer overflow when uploading a specially crafted file on the controller over FTP.
https://www.se.com/ww/en/download/document/SEVD-2020-315-01/