Discourse vulnerable to Cross-site Scripting through pending post titles descriptions

Vulnerability Description

Discourse is an option source discussion platform. Prior to version 2.8.14 on the `stable` branch and version 3.0.0.beta16 on the `beta` and `tests-passed` branches, pending post titles can be used for cross-site scripting attacks. Pending posts can be created by unprivileged users when a category has the "require moderator approval of all new topics" setting set. This vulnerability can lead to a full XSS on sites which have modified or disabled Discourse’s default Content Security Policy. A patch is available in versions 2.8.14 and 3.0.0.beta16.

References

• https://github.com/discourse/discourse/security/advisories/GHSA-ggq4-4qxc-c462
• https://github.com/discourse/discourse/commit/c0e2d7badac276d82a4056a994b48d68a8993a12