The ThirstyAffiliates – Affiliate Links, Link Branding, Link Tracking & Marketing Plugin plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'comment' parameter in all versions up to, and including, 3.12.1 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This vulnerability is only exploitable on block themes (such as Twenty Twenty-Five) where the Comment Content block causes comment HTML to flow through render_block, triggering the plugin's transformer. Additionally, a successful attack requires the attacker to have had one prior comment approved, after which subsequent crafted comments are auto-approved and rendered publicly.