The weak point is the UPS management card, not the rack hardware. If an attacker gets into that admin plane, the card can become a control point for power continuity, which means a clean shutdown or stable uptime is no longer guaranteed.
Claroty’s Team82 found two critical flaws in Vertiv Liebert IS-UNITY-DP and RDU101 cards: an authentication bypass on the web interface and a stack-based buffer overflow that can lead to remote code execution. Vertiv says firmware is available in 1.9.1.2_0000001 for Liebert RDU101 and 8.4.3.1_00160 for IS-UNITY devices.
The operational risk is wider than a normal appliance bug. These cards sit in the path that keeps dependent systems online or shuts them down safely, so compromise can create a direct outage trigger across data center and critical infrastructure environments.