ESAPI (The OWASP Enterprise Security API) is a free, open source, web application security control library. Prior to version 2.3.0.0, the default implementation of `Validator.getValidDirectoryPath(String, String, File, boolean)` may incorrectly treat the tested input string as a child of the specified parent directory. This potentially could allow control-flow bypass checks to be defeated if an attack can specify the entire string representing the 'input' path. This vulnerability is patched in release 2.3.0.0 of ESAPI. As a workaround, it is possible to write one's own implementation of the Validator interface. However, maintainers do not recommend this.