A specially crafted configuration file could be used to cause a stack-based buffer overflow condition in the OPCTest.exe, which may allow remote code execution on Opto 22 PAC Project Professional versions prior to R9.4008, PAC Project Basic versions prior to R9.4008, PAC Display Basic versions prior to R9.4g, PAC Display Professional versions prior to R9.4g, OptoOPCServer version R9.4c and prior that were installed by PAC Project installer, versions prior to R9.4008, and OptoDataLink version R9.4d and prior that were installed by PAC Project installer, versions prior to R9.4008. Opto 22 suggests upgrading to the new product version as soon as possible.