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 within the /boafrm/formDdns file. The issue arises from improper validation and handling of the submit-url argument, which can be manipulated by a remote attacker to overflow the stack buffer. This overflow can corrupt the stack, potentially allowing the attacker to execute arbitrary code on the device with the privileges of the affected process. The attack vector is remote network access, requiring no authentication or user interaction, making it highly exploitable. The vulnerability has a CVSS 4.0 base score of 8.7, reflecting its high severity due to the ease of exploitation and the critical impact on confidentiality, integrity, and availability. Although no known exploits are currently active in the wild, the public disclosure of the exploit code increases the likelihood of exploitation attempts. The affected device, D-Link DWR-M960, is a 4G LTE router commonly used in various regions for internet connectivity, making this vulnerability a significant concern for organizations relying on this hardware for network access and security. The lack of an official patch link indicates that mitigation may require vendor intervention or alternative protective measures until a firmware update is released.

The impact of CVE-2026-2855 is substantial for organizations using the D-Link DWR-M960 router. Exploitation can lead to arbitrary code execution, allowing attackers to gain control over the device. This can result in unauthorized access to internal networks, interception or manipulation of network traffic, disruption of internet connectivity, and potential pivoting to other internal systems. Confidentiality is at risk as attackers may intercept sensitive data; integrity can be compromised by altering device configurations or injecting malicious payloads; availability may be affected through denial-of-service conditions or device bricking. Given the router's role as a network gateway, successful exploitation could undermine the security posture of entire organizational networks. The remote, unauthenticated nature of the vulnerability increases the risk of widespread exploitation, especially in environments where these routers are exposed to untrusted networks or the internet. The absence of known active exploits currently provides a limited window for proactive defense, but the public availability of exploit code heightens urgency for mitigation.

1. Immediate mitigation should focus on isolating the affected D-Link DWR-M960 devices from untrusted networks, especially the internet, to reduce exposure to remote attacks. 2. Network segmentation should be employed to limit the router's access to critical internal systems. 3. Monitor network traffic for unusual patterns or attempts to access the /boafrm/formDdns endpoint, which may indicate exploitation attempts. 4. Implement strict firewall rules to restrict access to the router's management interfaces and DDNS settings handler. 5. Regularly check for firmware updates or security advisories from D-Link and apply patches promptly once available. 6. If patching is delayed, consider deploying intrusion detection/prevention systems (IDS/IPS) with signatures targeting this vulnerability or exploit attempts. 7. Conduct security audits and vulnerability scans on network devices to identify and remediate similar risks. 8. Educate network administrators about the vulnerability and ensure secure configuration practices are followed to minimize attack surface.