P4 programmable data-planes provide operators with a flexible method to set up data-plane forwarding logic. To deploy networks with confidence, a switch's forwarding logic should correspond with its intended behavior. Programs loaded onto programmable data-planes don't necessarily go through as much testing as traditional fixed-function devices from large manufacturers. Security is therefore of utmost importance. The main question this research attempts to answer, is whether a single compromised P4 switch can corrupt the entire (P4) network. In this scenario the attacker already has access to the compromised switch, and the assumption is made that all devices blindly trust each other. Two load balancing schemes are investigated, Clove-ECN and HULA. The former performs load balancing on the hosts, and results show that switches can transparently influence traffic flow by manipulating the ECN bits. The latter is designed for implementation on the data-plane, e.g. using P4, and we can conclude that HULA is susceptible to attacks by spoofing probe packets with false data.