The current IDE version is in beta, with no other versions supported. This is due to the extreme amounts of changes to the IDE internally.

To report a vulnerability you may email us at security@ms-paint-i.de or contact the developer on Discord at RubbaBoy#2832, though the former being preferred. Security updates will be posted on the GitHub security alerts tab of the repository. Updates should be expected very soon depending on how complex the vulnerability is, as they take priority over any other features of bug fixes.

More information will be available both here and elsewhere in the repository about security vulnerability reporting/other information as the project progresses and I gain a better understanding of the GitHub Security feature.