The Reaction Buttons plugin for WordPress is vulnerable to Stored Cross-Site Scripting via admin settings in all versions up to, and including, 2.1.6 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with administrator-level permissions and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This only affects multi-site installations and installations where unfiltered_html has been disabled.

AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N

CWE-79

https://wordpress.org/plugins/reaction-buttons/#developers

https://www.wordfence.com/threat-intel/vulnerabilities/id/9f5a77d1-b575-4e7c-bf27-fc78260de302?source=cve