The Stackable – Page Builder Gutenberg Blocks plugin for WordPress is vulnerable to CSS Injection in all versions up to, and including, 3.13.6. This makes it possible for unauthenticated attackers to embed untrusted style information into comments resulting in a possibility of data exfiltration such as admin nonces with limited impact. These nonces could be used to perform CSRF attacks within a limited time window. The presence of other plugins may make additional nonces available, which may pose a risk in plugins that don't perform capability checks to protect AJAX actions or other actions reachable by lower-privileged users.