Authenticated Denial-of-Service in Zigbee GetGroupMembership Handling

In EmberZNet 9.1.1 and earlier, a malformed GetGroupMembership message can result in an out-of-bounds write leading to a crash. A limited number of values can be written using this vulnerability, so no route to remote code execution was observed. These messages must come from a device that has already joined the network. Only devices supporting the Group Cluster are impacted.