GHSA-j2pq-22jj-4pm5 XWiki allows remote code execution through the extension sheet

• Maven org.xwiki.platform:xwiki-platform-repository-server-ui: >= 3.3-milestone-1, < 15.10.9 → fixed in 15.10.9 • Maven org.xwiki.platform:xwiki-platform-repository-server-ui: >= 16.0.0-rc-1, < 16.3.0 → fixed in 16.3.0

Impact On instances where `Extension Repository Application` is installed, any user can execute any code requiring `programming` rights on the server. In order to reproduce on an instance, as a normal user without `script` nor `programming` rights, go to your profile and add an object of type `ExtensionCode.ExtensionClass`. Set the description to `{{async}}{{groovy}}println("Hello from Description"){{/groovy}}{{/async}}` and press `Save and View`. If the description displays as `Hello from Description` without any error, then the instance is vulnerable. Patches This vulnerability has been fixed in XWiki 15.10.9 and 16.3.0. Workarounds Since `Extension Repository Application` is not mandatory, it can be safely disabled on instances that do not use it. It is also possible to manually apply this patch to the page `ExtensionCode.ExtensionSheet`, as well as this patch to the page `ExtensionCode.ExtensionAuthorsDisplayer`. References • https://jira.xwiki.org/browse/XWIKI-21890 • https://github.com/xwiki/xwiki-platform/commit/8659f17d500522bf33595e402391592a35a162e8 For more information If you have any questions or comments about this advisory: • Open an issue in Jira XWiki.org • Email us at Security Mailing List