Improper Access Control
An issue was discovered in Plataformatec Devise before 4.7.1. It confirms accounts upon receiving a request with a blank confirmation_token, if a database record has a blank value in the confirmation_token column. (However, there is no scenario within Devise itself in which such database records would exist.)
CWE-284 - Improper Access Control
Listed 5th in the 'OWASP Top Ten', improper (or broken) access control attacks are a fundamental type of vulnerability. This includes a broad range of design flaws that enable users to act outside of their intended permissions. They can use these privileges to gain access to restricted files and functionality such as accessing restricted information, falsifying records, destroying data, or executing commands.