CVE-2025-7704 identifies a stack-based buffer overflow vulnerability (CWE-121) in the Insyde SMASH shell program embedded within the Supermicro SYS-111C-NR Baseboard Management Controller (BMC) firmware, specifically version 1.04.11. The vulnerability is caused by improper bounds checking on input data processed by the SMASH shell, which leads to a stack overflow condition. This flaw can be exploited by an attacker with local privileges (PR:L) over a network (AV:N) without requiring user interaction (UI:N). The overflow can corrupt the stack, potentially allowing an attacker to alter program control flow, leading to denial of service or limited integrity compromise. The CVSS v3.1 score is 5.4, reflecting medium severity with no confidentiality impact but partial integrity and availability impacts. The vulnerability affects the BMC, a critical management component that allows remote monitoring and control of server hardware independent of the host OS. No patches or exploits are currently published, but the risk lies in potential escalation of privileges or disruption of server management functions. The vulnerability is particularly relevant for organizations relying on Supermicro SYS-111C-NR servers for critical infrastructure management. Mitigation currently focuses on restricting access to BMC interfaces and monitoring for suspicious activity until a patch is released.

For European organizations, this vulnerability poses a risk to the integrity and availability of server management systems. Exploitation could disrupt out-of-band management capabilities, potentially causing denial of service or unauthorized modification of management functions. This can impact data center operations, cloud service providers, and enterprises relying on Supermicro hardware for critical infrastructure. The lack of confidentiality impact reduces the risk of data leakage, but operational disruptions could lead to downtime and increased incident response costs. Organizations with extensive server deployments using the affected BMC firmware version are at higher risk. The vulnerability could also be leveraged as a foothold for further attacks within the network if combined with other vulnerabilities. Given the medium severity and no known exploits, the immediate risk is moderate but warrants proactive mitigation to prevent escalation.

1. Immediately restrict network access to the BMC interfaces of SYS-111C-NR servers to trusted administrators only, preferably via isolated management networks or VPNs. 2. Implement strict role-based access control (RBAC) and multi-factor authentication (MFA) for BMC access to reduce the risk of unauthorized exploitation. 3. Monitor BMC logs and network traffic for unusual activity or signs of exploitation attempts targeting the SMASH shell. 4. Coordinate with Supermicro for timely release and deployment of firmware patches addressing this vulnerability. 5. Conduct regular vulnerability scans and penetration tests focusing on BMC components to identify potential exploitation vectors. 6. Educate IT and security teams about the risks associated with BMC vulnerabilities and enforce policies to minimize exposure. 7. Consider network segmentation to isolate management interfaces from general user and application networks. 8. Maintain an inventory of affected hardware and firmware versions to prioritize patching and mitigation efforts.