XWiki Platform is a generic wiki platform offering runtime services for applications built on top of it. XWiki is vulnerable to reflected cross-site scripting (RXSS) via the `rev` parameter that is used in the content of the content menu without escaping. If an attacker can convince a user to visit a link with a crafted parameter, this allows the attacker to execute arbitrary actions in the name of the user, including remote code (Groovy) execution in the case of a user with programming right, compromising the confidentiality, integrity and availability of the whole XWiki installation. This has been patched in XWiki 15.6 RC1, 15.5.1 and 14.10.14. The patch in commit `04e325d57` can be manually applied without upgrading (or restarting) the instance. Users are advised to upgrade or to manually apply the patch. There are no known workarounds for this vulnerability.