IBM MQ is vulnerable to denial of service. An attacker is able to crash the system via maliciously crafted PCF messages.
exchange.xforce.ibmcloud.com/vulnerabilities/162084
supportcontent.ibm.com/support/pages/node/886885
www.ibm.com/blogs/psirt/ibm-security-bulletin-ibm-mq-and-ibm-mq-appliance-command-server-is-vulnerable-to-a-denial-of-service-attack-caused-by-specially-crafted-pcf-messages-cve-2019-4378/
www.ibm.com/support/pages/security-bulletin-ibm-mq-and-ibm-mq-appliance-command-server-vulnerable-denial-service-attack-caused-specially-crafted-pcf-messages-cve-2019-4378