Remote Stack-based Buffer Overflow in D-Link DIR-878

D-Link DIR-878 routers running firmware version 120B05 contain a critical stack-based buffer overflow vulnerability in the SetDynamicDNSIPv6Settings function. This vulnerability resides within the device's Dynamic DNS IPv6 settings component. An unauthenticated remote attacker can exploit this flaw by sending a specially crafted request containing malicious input in the IPv6Address or Hostname arguments to the vulnerable function. Successful exploitation allows for arbitrary code execution with the privileges of the web service process. Given the nature of the overflow, it likely facilitates remote exploitation without requiring local access or previous authentication. This poses a significant risk to the availability and integrity of affected network edge devices.

Impact

Successful exploitation of this vulnerability allows an attacker to achieve remote code execution on the router. This can lead to total device compromise, allowing the attacker to intercept network traffic, modify DNS settings for man-in-the-middle attacks, or utilize the compromised device as a pivot point for further lateral movement within the local area network.

Recommendation

• Monitor for unauthorized attempts to access or modify dynamic DNS configurations on network edge devices.
• Audit network access control lists to ensure web management interfaces of routers like the D-Link DIR-878 are not exposed to the public internet.
• Contact D-Link support or check official vendor channels immediately for firmware updates that address the identified CVE-2026-90692 vulnerability.