Maintenance Server, in Cybellums QCOW air-gapped distribution (China Edition), versions 2.15.5 through 2.27, was compiled with a hard-coded private cryptographic key.
An attacker with administrative privileges & access to the air-gapped server could potentially use this key to run commands on the server. The issue was resolved in version 2.28. Earlier versions, including all Cybellum 1.x versions, and distributions for the rest of the world remain unaffected.