A critical stack-based buffer overflow in D-Link DIR-816 routers enables remote code execution, creating a high risk of unauthorized system access.

This vulnerability involves a stack-based buffer overflow in the goahead component, specifically within the form2RepeaterStep2.cgi file. An unauthenticated remote attacker can exploit this by sending specially crafted input to the key1, key2, key3, key4, or pskValue parameters.

The severity of this flaw, rated at 9.8, indicates that unauthorized parties could potentially gain full control over the router. This access facilitates the interception of network traffic, redirection of user sessions, and broad reconnaissance of the internal network, posing a severe threat to organizational security.

Immediate Action: Since the product has reached end-of-life status, the recommended course of action is to replace the hardware immediately.

Proactive Monitoring: Review system and firewall logs for suspicious web requests targeting the /goform/form2RepeaterStep2.cgi file.

Compensating Controls: Restrict access to the router's web interface to trusted internal IP addresses only via a secure gateway.

Public Exploit Available: Yes

The presence of a publicly available exploit necessitates immediate action to mitigate the risk. Organizations should prioritize replacing these unsupported devices as they cannot be secured against this critical vulnerability.