CVE-2026-105302A flaw was found in the User Session Note mapper of the Keycloak identity and access management solution. The issue occurs because the mapper does not validate whether a requested session note contains sensitive internal credentials, such as federated access tokens from external identity providers. This allows a delegated client administrator to leak a user's upstream bearer tokens into the tokens issued to their managed application, potentially leading to unauthorized access to the user's data on external platforms.