Rockwell Automation was made aware of a vulnerability by a security researcher from Georgia Institute of Technology that the MicroLogix 1100 and 1400 controllers contain a vulnerability that may give an attacker the ability to accomplish remote code execution. The vulnerability is an unauthenticated stored cross-site scripting vulnerability in the embedded webserver. The payload is transferred to the controller over SNMP and is rendered on the homepage of the embedded website.
https://rockwellautomation.custhelp.com/app/answers/answer_view/a_id/1137679