In Apache Wicket 1.5.10 or 6.13.0, by issuing requests to special urls handled by Wicket, it is possible to check for the existence of particular classes in the classpath and thus check whether a third party library with a known security vulnerability is in use.

Unspecified vulnerability in Apache Wicket 1.4.x before 1.4.23, 1.5.x before 1.5.11, and 6.x before 6.8.0 allows remote attackers to obtain sensitive information via vectors that cause raw HTML templates to be rendered without being processed and reading the information that is outside of wicket:panel markup.