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 Psi+ (0.16.563.580 - 0.16.571.627).
https://github.com/psi-im/iris/pull/47/commits/02e976d4426a1319a7af7d26d7aba9d8c6077570