Gajim through 0.16.7 unconditionally implements the "XEP-0146: Remote Controlling Clients" extension. This can be abused by malicious XMPP servers to, for example, extract plaintext from OTR encrypted sessions.
https://security.gentoo.org/glsa/201707-14
https://mail.jabber.org/pipermail/standards/2016-August/031335.html
https://dev.gajim.org/gajim/gajim/issues/8378
https://dev.gajim.org/gajim/gajim/commit/cb65cfc5aed9efe05208ebbb7fb2d41fcf7253cc