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, parsing posts can be susceptible to regular expression denial of service (ReDoS) attacks. This issue is patched in versions 2.8.14 and 2.9.0.beta16. There are no known workarounds.