Affected software: https://jappix.org/
Discovered by: Provensec
Type of vulnerability: XSS Stored
Description: Jappix is a new, smart and powerful social platform. We think each of us should own his own data, that’s why we’ve made Jappix decentralized. Jappix is one of the smartest free social network. You can install it on your own server if you have one or join one of the existings. All of the Jappix servers are connected together through XMPP protocol. Therefore, you can use a jappix account with other software, as Gajim, Psi, iChat or Movim.
Proof of concept:
Create new account and fill the nickname and other field with "><script>alert(document.cookie);</script> and then goto https://firstname.lastname@example.org/contact