Discourse is an open-source discussion platform. Prior to version 2.9.0.beta13, users can post chat messages of an unlimited length, which can cause a denial of service for other users when posting huge amounts of text. Users should upgrade to version 2.9.0.beta13, where a limit has been introduced. No known workarounds are available.
https://github.com/discourse/discourse/security/advisories/GHSA-mfh7-6cv6-qccc
https://github.com/discourse/discourse/commit/3de765c89524a526ce611e11468d758a471a933f