Multiple cross-site scripting (XSS) vulnerabilities in GET requests in FreshRSS 1.11.1 allow remote attackers to inject arbitrary web script or HTML via the (1) c parameter or (2) a parameter.
https://www.exploit-db.com/exploits/45954/
http://seclists.org/fulldisclosure/2018/Dec/3
http://packetstormsecurity.com/files/150608/FreshRSS-1.11.1-Cross-Site-Scripting.html