A missing validation check allowed users to redeem subscription offers that were no longer active.

This vulnerability is present in Ghost from v4.22.0 up to v6.54.0.

v6.54.1 contains a fix for this issue.

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.

If your Ghost is a Ghost-CLI install see our documentation on updating it to the latest version here.

Ghost thanks Pedro Pinho for disclosing this vulnerability responsibly.

If you have any questions or comments about this advisory, email us at security@ghost.org.