WordPress Admin Font Editor plugin indexisto 1.8 and before contains a cross-site scripting vulnerability which allows an attacker to execute arbitrary script code in the browser of an unsuspecting user in the context of the affected site. This can allow the attacker to steal cookie-based authentication credentials and launch other attacks.
View the template here CVE-2016-1000138.yaml
References:
https://nvd.nist.gov/vuln/detail/CVE-2016-1000138