miniOrange WordPress SAML SSO multiple versions - Open Redirect in SSO login

The SAML SSO Standard WordPress plugin version 16.0.0 before 16.0.8, SAML SSO Premium WordPress plugin version 12.0.0 before 12.1.0 and SAML SSO Premium Multisite WordPress plugin version 20.0.0 before 20.0.7 does not validate that the redirect parameter to its SSO login endpoint points to an internal site URL, making it vulnerable to an Open Redirect issue when the user is already logged in.