GHSA-wcg9-pgqv-xm5v XWiki Platform allows XSS through XClass name in string properties

• Maven org.xwiki.platform:xwiki-platform-oldcore: >= 1.1.2, < 14.10.21 → fixed in 14.10.21 • Maven org.xwiki.platform:xwiki-platform-oldcore: >= 15.0-rc-1, < 15.5.5 → fixed in 15.5.5 • Maven org.xwiki.platform:xwiki-platform-oldcore: >= 15.6-rc-1, < 15.10.6 → fixed in 15.10.6 • Maven org.xwiki.platform:xwiki-platform-oldcore: >= 16.0.0-rc-1, < 16.0.0 → fixed in 16.0.0

Impact Is it possible for a user without Script or Programming rights to craft a URL pointing to a page with arbitrary JavaScript. This requires social engineer to trick a user to follow the URL. Reproduction steps 1. As a user without script or programming right, create a (non-terminal) document named `" + alert(1) + "` (the quotes need to be part of the name). 1. Edit the class. 1. Add a string property named `"test"`. 1. Edit using the object editor and add an object of the created class 1. Get an admin to open `/xwiki/bin/view/%22%20%2B%20alert(1)%20%2B%20%22/?viewer=display&type=object&property=%22%20%2B%20alert(1)%20%2B%20%22.WebHome.test&mode=edit` where `` is the URL of your XWiki installation. Patches This has been patched in XWiki 14.10.21, 15.5.5, 15.10.6 and 16.0.0. Workarounds We're not aware of any workaround except upgrading. References • https://jira.xwiki.org/browse/XWIKI-21810 • https://github.com/xwiki/xwiki-platform/commit/27eca8423fc1ad177518077a733076821268509c