CVE-2026-2857 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 Port Forwarding Configuration Endpoint, specifically within the function sub_423E00 located in the /boafrm/formPortFw file. The issue arises from improper handling of the submit-url argument, which can be manipulated remotely to overflow the stack buffer. This overflow can corrupt the execution stack, enabling an attacker to execute arbitrary code with elevated privileges on the device. The vulnerability requires no authentication or user interaction, making it remotely exploitable over the network. The CVSS 4.0 base score of 8.7 reflects the high impact on confidentiality, integrity, and availability, combined with the ease of exploitation (network vector, no privileges required). 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 widely deployed 4G LTE router used in both consumer and enterprise environments, often serving as a critical network gateway. The vulnerability could allow attackers to gain persistent control over the device, intercept or manipulate network traffic, disrupt services, or pivot to internal networks.

The impact of CVE-2026-2857 is significant for organizations using the D-Link DWR-M960 router, as exploitation can lead to complete compromise of the device. Attackers can execute arbitrary code remotely without authentication, potentially gaining control over network traffic and connected devices. This can result in data breaches, interception of sensitive communications, disruption of network services, and establishment of persistent backdoors. For enterprises, this could mean lateral movement within internal networks, leading to broader compromise. The vulnerability threatens confidentiality, integrity, and availability of network infrastructure. Given the router's role as a gateway device, successful exploitation can undermine perimeter security and expose internal systems to external attackers. The lack of current known exploits in the wild provides a window for mitigation, but the public disclosure elevates the risk of imminent attacks. Organizations relying on these routers in critical environments such as government, healthcare, finance, and telecommunications face heightened risk.

1. Immediately monitor vendor communications for official patches or firmware updates addressing CVE-2026-2857 and apply them as soon as they become available. 2. Until patches are released, restrict access to the router's management interface by limiting IP addresses allowed to connect, ideally isolating it from the public internet. 3. Disable remote management features if not strictly necessary to reduce the attack surface. 4. Implement network segmentation to isolate vulnerable devices from critical internal networks, minimizing potential lateral movement. 5. Employ intrusion detection and prevention systems (IDS/IPS) to monitor for anomalous traffic patterns targeting the /boafrm/formPortFw endpoint or unusual submit-url parameters. 6. Conduct regular security audits and vulnerability scans to identify devices running the affected firmware version. 7. Educate network administrators about the vulnerability and signs of exploitation to enable rapid incident response. 8. Consider deploying network-level filtering to block suspicious payloads that could trigger the buffer overflow. 9. Maintain up-to-date backups of router configurations and network device states to facilitate recovery if compromise occurs.