pretalx 2.3.1 before 2.3.2 allows path traversal in HTML export (a non-default feature). Organizers can trigger the overwriting (with the standard pretalx 404 page content) of an arbitrary file.
https://www.sonarsource.com/blog/pretalx-vulnerabilities-how-to-get-accepted-at-every-conference/
https://pretalx.com/p/news/security-release-232/
https://github.com/pretalx/pretalx/releases/tag/v2.3.2
https://github.com/pretalx/pretalx/commit/60722c43cf975f319e94102e6bff320723776890