faces/context/PartialViewContextImpl.java in Eclipse Mojarra, as used in Mojarra for Eclipse EE4J before 2.3.10 and Mojarra JavaServer Faces before 2.2.20, allows Reflected XSS because a client window field is mishandled.

It was found that Mojarra JSF would not properly escape user-supplied content in certain circumstances. The contents of outputText tags and raw EL expressions that immediately follow <script> or <style> elements were not escaped. If a remote attacker could trick a user into visiting a specially-crafted URL, it would lead to arbitrary web script execution in the user's browser.