Discourse is an open-source discussion platform. Prior to version 3.2.3 on the "stable" branch and version 3.3.0.beta4 on the "beta" and "tests-passed" branches, a malicious actor could get the FastImage library to redirect requests to an internal Discourse IP. This issue is patched in version 3.2.3 on the "stable" branch and version 3.3.0.beta4 on the "beta" and "tests-passed" branches. No known workarounds are available.