CVE-2026-2855 is a stack-based buffer overflow vulnerability identified in the D-Link DWR-M960 router firmware version 1.01.07. The vulnerability resides in the DDNS Settings Handler component, specifically in the function sub_4648F0 located in the /boafrm/formDdns file. The issue arises when the submit-url argument is manipulated with crafted input, leading to a stack-based buffer overflow condition. This overflow can corrupt the stack, potentially allowing an attacker to overwrite the return address or other control data, enabling arbitrary code execution on the device. The vulnerability is remotely exploitable over the network without requiring authentication or user interaction, increasing its severity and ease of exploitation. The CVSS 4.0 base score is 8.7, reflecting high impact on confidentiality, integrity, and availability, with low attack complexity and no privileges or user interaction needed. Although no active exploits have been reported in the wild, the public disclosure of exploit details raises the likelihood of future attacks. The affected device is a widely used 4G LTE router model, often deployed in enterprise and consumer environments for internet connectivity. Successful exploitation could allow attackers to take full control of the device, intercept or manipulate network traffic, disrupt service, or pivot into internal networks.

The impact of CVE-2026-2855 is significant for organizations relying on the D-Link DWR-M960 router for network connectivity. Exploitation can lead to complete compromise of the device, enabling attackers to execute arbitrary code with elevated privileges. This can result in unauthorized access to internal networks, interception or manipulation of sensitive data, disruption of network services, and potential lateral movement to other systems. The vulnerability threatens confidentiality by exposing network traffic, integrity by allowing malicious modifications, and availability by potentially causing device crashes or denial of service. Given the remote and unauthenticated nature of the exploit, attackers can target vulnerable devices over the internet, increasing the attack surface. Organizations in sectors such as telecommunications, government, healthcare, and critical infrastructure that deploy these routers face heightened risks. The public disclosure of exploit details further elevates the threat, as it enables attackers to develop and deploy exploits rapidly.

To mitigate CVE-2026-2855, organizations should immediately verify if they are using the D-Link DWR-M960 router with firmware version 1.01.07 and prioritize upgrading to a patched firmware version once released by D-Link. In the absence of an official patch, network administrators should restrict remote access to the router’s management interfaces by implementing firewall rules that limit access to trusted IP addresses only. Disabling DDNS functionality or the vulnerable DDNS Settings Handler component, if feasible, can reduce exposure. Network segmentation should be employed to isolate vulnerable devices from critical internal resources. Continuous monitoring of network traffic for anomalous patterns targeting the /boafrm/formDdns endpoint is recommended to detect exploitation attempts. Employing intrusion detection/prevention systems (IDS/IPS) with signatures for this vulnerability can provide additional defense. Regularly reviewing vendor advisories and threat intelligence feeds will help maintain awareness of emerging exploits and patches. Finally, organizations should consider replacing affected devices with models that have a stronger security posture if patching is delayed.