Ghost: Paid gift memberships obtainable at minimal cost via the donations feature

Impact

A vulnerability in Ghost's public donation checkout flow allowed an unauthenticated attacker to obtain full paid gift memberships for a minimal payment. No customer or member data was exposed, and the issue could not be used to steal money from a site or its members.

Vulnerable versions

This vulnerability is present in Ghost from v6.27.0 up to v6.43.1.

Patches

v6.44.0 contains a fix for this issue.

How to update

For self-hosters using Docker, find Docker’s official Ghost image on Docker Hub and follow the documentation on updating a Docker-based Ghost instance.

For self-hosters using Ghost-CLI, see the documentation for updating Ghost to the latest version.

Workarounds

If upgrading immediately is not possible, you can remove the vulnerable checkout path by disabling the donations feature in Ghost Admin under Settings → Membership → Tips & donations until the upgrade is applied.

References

Ghost thanks sane100400 and p4p3r for disclosing this vulnerability responsibly.

For more information

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