Indico is an event management system that uses Flask-Multipass, a multi-backend authentication system for Flask. Prior to version 3.3.8, there is a Cross-Site-Scripting vulnerability when rendering LaTeX math code in contribution or abstract descriptions. Users should to update to Indico 3.3.8 as soon as possible. As a workaround, only let trustworthy users create content on Indico. Note that a conference doing a Call for Abstracts actively invites external speakers (who the organizers may not know and thus cannot fully trust) to submit content, hence the need to update to a a fixed version ASAP in particular when using such workflows.