An incorrect implementation of "XEP-0280: Message Carbons" in multiple XMPP clients allows a remote attacker to impersonate any user, including contacts, in the vulnerable application's display. This allows for various kinds of social engineering attacks. This CVE is for Jitsi 2.5.5061 - 2.9.5544.
https://rt-solutions.de/wp-content/uploads/2017/02/CVE-2017-5589_xmpp_carbons.pdf
https://rt-solutions.de/en/2017/02/CVE-2017-5589_xmpp_carbons/
https://github.com/jitsi/jitsi/commit/7d66da61b316c9480b63000f831b6de723b87315