In 2010, OWASP added "Unvalidated Redirects and Forwards" to its Top 10 list and merged it into "Sensitive Data Exposure" in 2013. Open redirects are often overlooked, and their impact is not always well understood. At first, it does not look like a big deal. The user is receiving a 3xx status code and is being redirected to another URL. That target URL should handle all authentication and access control, regardless of where the data originated.