GHSA-mpwq-j3xf-7m5w The redirect_uri validation logic allows for bypassing explicitly allowed hosts that would otherwise be restricted

• Maven org.keycloak:keycloak-services: < 23.0.3 → fixed in 23.0.3

An issue was found in the redirect_uri validation logic that allows for a bypass of otherwise explicitly allowed hosts. The problem arises in the verifyRedirectUri method, which attempts to enforce rules on user-controllable input, but essentially causes a desynchronization in how Keycloak and browsers interpret URLs. Keycloak, for example, receives "www%2ekeycloak%2eorg%2fapp%2f:[email protected]" and thinks the authority to be keycloak.org when it is actually example.com. This happens because the validation logic is performed on a URL decoded version, which no longer represents the original input. Acknowledgements Karel Knibbe