High Quality Content by WIKIPEDIA articles! HTTP header injection is a general class of web application security vulnerability which occurs when Hypertext Transfer Protocol (HTTP) headers are dynamically generated based on user input. Header injection in HTTP responses can allow for HTTP response splitting, Session fixation via the Set-Cookie header, cross-site scripting (XSS), and malicious redirects attacks via the location header. HTTP header injection is a relatively new area for web-based attacks, and has primarily been pioneered by Amit Klein in his work on request/response smuggling/splitting.