CubeCart is an ecommerce software solution. Prior to version 6.5.11, a logic flaw exists in the newsletter subscription endpoint that allows an attacker to unsubscribe any user without their consent. By changing the value of the force_unsubscribe parameter in the POST request to 1, an attacker can force the removal of any valid subscriber’s email address. This issue has been patched in version 6.5.11.
https://github.com/cubecart/v6/security/advisories/GHSA-869v-gjv8-9m7f
https://github.com/cubecart/v6/commit/dbc58cf1f7a6291f7add5893b56bff7920a29128
https://github.com/cubecart/v6/commit/db965fcfa260c4f17eb16f8c5494e5af4a8ac271
https://github.com/cubecart/v6/commit/7fd1cd04f5d5c3ce1d7980327464f0ff6551de79