Report a security problem privately, not in a public issue: on the repository's Security tab, choose Report a vulnerability. Only you and the maintainer see the report until a fix is out.

A security problem is anything that lets another program or another account:

• open a keyboard, a mouse, a headset or /dev/uinput through the udev rules Gearbench installs, beyond what the user guide's The udev rules says each rule grants;
• send a request to the Gearbench service, or read its replies, from another account;
• have Gearbench write a file or run a command it would not otherwise;
• have Gearbench send a device something it would not send otherwise.

Say which version you run (gearbench-ctl --version), what you did and what happened. The fix comes in a new release.