GHSA-chgm-3698-jm42

Ghost: Member existence leak via magic link sign-in response

### Impact A discrepancy in responses from the members signin endpoints made it possible for an unauthenticated attacker to determine whether a given email address belongs to a registered member of a Ghost site. ### Vulnerable versions This vulnerability is present in Ghost from v5.18.0 up to v6.21.0. ### Patches v6.21.1 contains a fix for this issue. ### How to update For self-hosters using Docker, find [Docker's official Ghost image here](https://hub.docker.com/_/ghost). Updating a Docker-based Ghost instance [is documented here](https://docs.ghost.org/install/docker#updating-ghost). If your Ghost is a Ghost-CLI install see our documentation on [updating it to the latest version here](https://docs.ghost.org/update). ### For more information If you have any questions or comments about this advisory, email Ghost at [security@ghost.org](mailto:security@ghost.org).