Zulip is an open-source team chat application. From versions 2.0.0-rc1 to before 10.4 in Zulip Server, the /digest/ URL of a server shows a preview of what the email weekly digest would contain. This URL, though not the digest itself, contains a cross-site scripting (XSS) vulnerability in both topic names and channel names. This issue has been fixed in Zulip Server 10.4. A workaround for this issue involves denying access to /digest/.
https://github.com/zulip/zulip/security/advisories/GHSA-vgf2-vw4r-m663
https://github.com/zulip/zulip/commit/6608c8777254e73a4b540e5e1c4af92e680a55fc
https://github.com/zulip/zulip/commit/1a8429e338ff53bdcc4b42e7e71b6fffdd84fcd1
https://github.com/zulip/zulip/commit/175ec1f365b0db982d6eac9019701cbf6e8bc2f2