An attacker could send a crafted HTTP/HTTPS request to render the web server unavailable and/or lead to remote code execution caused by a stack-based buffer overflow vulnerability. A cold restart is required for recovering CompactLogix 5370 L1, L2, and L3 Controllers, Compact GuardLogix 5370 controllers, and Armor Compact GuardLogix 5370 Controllers Versions 20 to 30.014 and earlier systems.