dde-daemon, the daemon process of DDE (Deepin Desktop Environment) 15.0 through 15.3, runs with root privileges and hardly does anything to identify the user who calls the function through D-Bus. Anybody can change the grub config, even to append some arguments to make a backdoor or privilege escalation, by calling DoWriteGrubSettings() provided by dde-daemon.
CWE-862 - Missing Authorization
The missing authorization vulnerability occurs when a software program allows users to access privileged parts of the program without verifying the user credentials. Impact of such a vulnerability depends on the resources employed by the software, ranging from account takeover to sensitive information exposure, denial of service, and complete system takeover.