An issue was discovered in GNOME GLib before 2.78.5, and 2.79.x and 2.80.x before 2.80.1. When a GDBus-based client subscribes to signals from a trusted system service such as NetworkManager on a shared computer, other users of the same computer can send spoofed D-Bus signals that the GDBus-based client will wrongly interpret as having been sent by the trusted system service. This could lead to the GDBus-based client behaving incorrectly, with an application-dependent impact.