A method, computer program product, and system for detecting vulnerabilities in web applications is described. A method may comprise determining one or more values associated with a web application that flow to response data associated with the web application. The one or more values may be modifiable by unreliable input. The method may further comprise generating a representation of the response data associated with the web application. The method may additionally comprise determining one or more potentially vulnerable portions of the response data based upon, at least in part, the one or more values modifiable by the unreliable input that flow to the response data associated with the web application, and the representation of the response data associated with the web application.