CVE-2026-20293

Secure Boot is meant to stop your server from running untrusted software before the operating system starts. This vulnerability lets a person who can get access to the device’s boot console (or physically control it) use the built-in firmware shell to weaken those protections, so the device may run unauthorized code too early to be blocked by normal software defenses. It’s like a locked front door (Secure Boot) being bypassed from the hallway because someone can reach the building’s security panel before the rest of the building comes online.

This matters to you if you run or manage Cisco UCS servers and UCS-based appliances from the affected product list. The bypass is possible when an attacker can reach the UEFI Shell at boot through local console access or physical control, and it may also work with low-privilege credentials (user/admin role). This is not a remote “internet-only” issue based on the findings—treat it as a serious risk only when the UEFI Shell/boot environment is reachable via local access or physical access.

This is RED because attackers have a practical path to disable a core security feature (Secure Boot) using the UEFI Shell when they can reach the boot interface, and a public exploit is available. Even if you think your servers are “locked down,” any weakness in physical access or console/boot policy can turn this into full pre-OS compromise. Act now to reduce who can touch the boot console and to obtain Cisco’s official mitigation or patch status for this exact CVE.