XWiki Platform is a generic wiki platform offering runtime services for applications built on top of it. Starting in version 4.3-milestone-1 and prior to versions 16.10.9, 17.4.2, and 17.5.0, the REST search URL is vulnerable to HQL injection via the orderField parameter. The specified value is added twice in the query, though, once in the field list for the select and once in the order clause, so it's not that easy to exploit. The part of the query between the two fields can be enclosed in single quotes to effectively remove them, but the query still needs to remain valid with the query two times in it. This has been patched in versions 17.5.0, 17.4.2, and 16.10.9. No known workarounds are available.