source: http://www.securityfocus.com/bid/889/info

ZBSoft ZBServer Pro is an Internet and Intranet server that supports HTTP, Gopher, FTP and Chat Services. ZBServer is available for Microsoft Windows operating systems.

ZBServer Pro 1.5 has an unchecked buffer in the code that handles GET requests. This weakness allows for the execution of arbitrary code. 

USSR exploit:
Binary exploit - 19688.exe
Source code - 19688.zip

https://github.com/offensive-security/exploitdb-bin-sploits/raw/master/bin-sploits/19688.exe

https://github.com/offensive-security/exploitdb-bin-sploits/raw/master/bin-sploits/19688.zip