If you discover an issue in PC^2 that represents a contest security problem (for example, an exploit where a contest team could somehow gain access to another team's code, or gain access to the judge's solutions), please do not file a GitHub "issue" on it. Doing so could potentially advertise the vulnerability and therefore affect many contests before we can address the problem and close the exploit.
Instead, please immediately send an email to the PC^2 maintainers at pc2@ecs.csus.edu. Please describe the issue in detail so that we can immediately investigate and work toward a rapid fix. Please include information on the environment (Windows, OS/X, Linux, etc.) in which the vulnerability was found.
If you have a proposed solution to the issue, please give as much information regarding your solution as possible. If you are interested in coding and contributing a fix yourself, even better! We welcome such contributions, and we'll work with you via email to arrange a "private issue" through which you can contribute your fix.