Casdoor is a UI-first Identity and Access Management (IAM) / Single-Sign-On (SSO) platform. In Casdoor 1.577.0 and earlier, a logic vulnerability exists in the beego filter CorsFilter that allows any website to make cross domain requests to Casdoor as the logged in user. Due to the a logic error in checking only for a prefix when authenticating the Origin header, any domain can create a valid subdomain with a valid subdomain prefix (Ex: localhost.example.com), allowing the website to make requests to Casdoor as the current signed-in user.