A critical buffer overflow vulnerability in H3C Magic B3 routers exposes devices to potential remote code execution and service disruption.

This vulnerability occurs due to improper memory handling in the AddMacList and EditMacList functions within the /goform/aspForm file. An attacker with low-level privileges can trigger a buffer overflow by sending a maliciously crafted param argument to the vulnerable endpoint.

Successful exploitation of this buffer overflow could result in complete loss of router availability or allow an attacker to execute arbitrary code on the underlying operating system. Given the CVSS score of 8.8, this poses a significant risk to network integrity and confidentiality. Compromise of edge networking hardware can provide an attacker with a foothold to conduct further lateral movement within the internal network.

Immediate Action: As there is currently no official patch available from the vendor, network administrators should restrict access to the router management interface to trusted IP addresses only. Disable remote management features if they are not strictly required for business operations.

Proactive Monitoring: Monitor device logs for unusual POST requests directed at /goform/aspForm and observe the router for unexpected reboots or service instability.

Compensating Controls: Implement a Web Application Firewall or network-based intrusion detection system to inspect and drop traffic containing abnormally long input strings in the param field of web requests directed at the router.

Public Exploit Available: Yes, a proof-of-concept is available via the researcher's published technical write-up on GitHub.

Due to the absence of a vendor-provided fix, this vulnerability represents a high-risk exposure for all deployed H3C Magic B3 units. Organizations should immediately isolate these devices from the public internet or apply strict access control lists to prevent unauthorized access to the web management interface. Security teams must prioritize replacing or decommissioning these devices if the vendor fails to provide a security update in a timely manner.