XWiki Platform is a generic wiki platform offering runtime services for applications built on top of it. Versions 6.2-milestone-1 through 16.10.9 and 17.0.0-rc-1 through 17.4.1 of both XWiki Platform Flamingo Skin Resources and XWiki Platform Web Templates are vulnerable to a reflected XSS attack through a deletion confirmation message. The attacker-supplied script is executed when the victim clicks the "No" button. This issue is fixed in versions 16.10.10 and 17.4.2 of both XWiki Platform Flamingo Skin Resources and XWiki Platform Web Templates.