Abstract: A system for monitoring and mitigating client-side exploitation of application flaws, the system comprising a client device operating an application, a server communicatively coupled to the client device, and an application flaw service module communicatively coupled to the client device and server in which the application flaw service module receives a request from the client device comprising transactional metadata and inspecting the transactional metadata for malicious content within the request. A method of monitoring and mitigating client-side exploitation of application flaws by adding computer usable program code to the response to a first request from a client, receiving a second request from the client, determining that transactional metadata within the response contains an attack vector, and returning a response to the browser including attack vector countermeasures embedded in the response.