Improper Server Certificate Validation in ZSIRep Client Library

The ZSIRep client library (ZSIREP.CLIENT.DLL) is vulnerable to improper server certificate validation. It registers a process-wide .NET callback that accepts any certificate for HTTPS connections without verification. This allows a man-in-the-middle attacker to impersonate the ZSIRep server and intercept or modify authentication data and documents. The callback persists after the client is closed, weakening other HTTPS connections in the same application.

The issue was fixed in version 2.12.3.1. The library is used in KS-SOMED (fixed in 2026.03.0.01), KS-PPS (fixed in 2026.03.1.0), KS-MEDIS (fixed in 2026.03.0.0), KS-SOLAB (fixed in 2026.3.1.0), and KS-ASW (fixed in 2026.3.0.1).