Cisco has released patches for a critical vulnerability in its out-of-band management solution, present in many of its servers and appliances. The flaw allows unauthenticated remote attackers to gain admin access to the Cisco Integrated Management Controller (IMC), which gives administrators remote control over servers even when the main OS is shut down.
The vulnerability, tracked as CVE-2026-20093, stems from incorrect handling of password changes and can be exploited by sending specially crafted HTTP requests. This means servers with their IMC interfaces exposed directly to the local network — or worse, to the internet — are at immediate risk.
The Cisco IMC is a baseboard management controller (BMC), a dedicated controller embedded into server motherboards with its own RAM and network interface that gives administrators monitoring and management capabilities as if they were physically connected to the server with a keyboard, monitor, and mouse (KVM). Because BMCs run their own firmware independently of the OS, they can be used to perform operations even when the OS is shut down, including reinstalling it.
