A flaw was found in the Qute template engine, which is used by Quarkus to generate dynamic content like HTML pages or emails. The issue exists in the component responsible for looking up data values (ReflectionValueResolver), which fails to properly block access to sensitive Java internal functions when processing certain data types like Enums. An attacker who can provide or influence the template text can exploit this bypass to take control of the server by executing unauthorized commands.
Applications utilizing the Quarkus Qute template engine should ensure that untrusted input is not directly incorporated into template content. Restricting access to the application's template rendering functionality to trusted sources can reduce the attack surface.