The (1) Windows and (2) Java client programs for the ATEN KH1516i IP KVM switch with firmware 1.0.063 and the KN9116 IP KVM switch with firmware 1.1.104 do not properly use RSA cryptography for a symmetric session-key negotiation, which makes it easier for remote attackers to (a) decrypt network traffic, or (b) conduct man-in-the-middle attacks, by repeating unspecified "client-side calculations."