Discourse allows self-XSS through malicious composer message

Discourse is an open-source messaging platform. In versions 2.8.10 and prior on the stable branch and versions 2.9.0.beta11 and prior on the beta and tests-passed branches, users composing malicious messages and navigating to drafts page could self-XSS. This vulnerability can lead to a full XSS on sites which have modified or disabled Discourse’s default Content Security Policy. This issue is patched in the latest stable, beta and tests-passed versions of Discourse.