The GUI component (aka PulseUI) in Pulse Secure Desktop Linux clients before PULSE5.2R9.2 and 5.3.x before PULSE5.3R4.2 does not perform strict SSL Certificate Validation. This can lead to the manipulation of the Pulse Connection set.
https://euvd.enisa.europa.eu/vulnerability/EUVD-2018-18131
http://www.securityfocus.com/bid/102908
http://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA43620