Discourse is an option source discussion platform. Prior to version 2.8.14 on the `stable` branch and version 2.9.0.beta16 on the `beta` and `tests-passed` branches, users can create posts with raw body longer than the `max_length` site setting by including html comments that are not counted toward the character limit. This issue is patched in versions 2.8.14 and 2.9.0.beta16. There are no known workarounds.
https://github.com/discourse/discourse/security/advisories/GHSA-p47g-v5wr-p4xp
https://github.com/discourse/discourse/commit/bf6b08670a927cc80bb090b7a2e710b4b554e6a8