This Cimy Counter plugin is prone to HTTP response-splitting and a cross-site scripting vulnerabilities. It fails properly clean up user-supplied input. An attacker may execute arbitrary script code in the browser of an user in the context of the affected site. In this way the attacker can steal cookie-based authentication credentials. Also, influence how web content is served or interpreted. Other attacks are also possible.
Upgrade the plugin.
Type Multi OWASP Top 10 A3: Cross Site Scripting (XSS)