Cisco UCS UEFI Secure Boot Bypass Vulnerability Disclosed

A vulnerability in the UEFI Shell implementation of Cisco UCS Servers allows unauthenticated attackers with physical access to bypass UEFI Secure Boot validation. This vulnerability arises from memory write commands available in the UEFI Shell when Secure Boot is enabled. Attackers can exploit this by selecting the UEFI Shell boot option and modifying UEFI memory variables, potentially executing unauthorized software. Cisco has released software updates to address this issue, but no workarounds are available. Affected products include various UCS Servers and appliances that support UEFI Secure Boot. The vulnerability is identified under CVE-2026-XXXX, and it poses a significant risk to systems where physical access is possible.

Key Points: • Cisco UCS Servers vulnerable to UEFI Secure Boot bypass. • Attackers with physical access can exploit the vulnerability. • Cisco has released updates; no workarounds available.