Under non-standard configurations, IBM WebSphere MQ might send password data in clear text over the network. This data could be intercepted using man in the middle techniques.
IBM WebSphere MQ 7.5 before 7.5.0.7 and 8.0 before 8.0.0.5 mishandles protocol flows, which allows remote authenticated users to cause a denial of service (channel outage) by leveraging queue-manager rights.