Wiki.js is al wiki app built on Node.js. Client side template injection was discovered, that could allow an attacker to inject malicious JavaScript into the content section of pages that would execute once a victim loads the page that contains the payload. This was possible through the injection of a invalid HTML tag with a template injection payload on the next line. This vulnerability is fixed in 2.5.303.
https://github.com/requarks/wiki/security/advisories/GHSA-xjcj-p2qv-q3rf
https://github.com/requarks/wiki/commit/1238d614e1599fefadd4614ee4b5797a087f50ac