ConvertKit < 2.4.9.1 - Missing Authorization

Description

The ConvertKit – Email Newsletter, Email Marketing, Subscribers and Landing Pages plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the tag_subscriber function in all versions up to, and including, 2.4.9. This makes it possible for unauthenticated attackers to subscribe users to tags. Financial damages may occur to site owners if their API quota is exceeded.