CVE-2026-2928: D-Link DWR-M960 Buffer Overflow Vulnerability

CVE-2026-2928 Overview

A stack-based buffer overflow vulnerability has been discovered in D-Link DWR-M960 firmware version 1.01.07. This critical security flaw exists within the WLAN Encryption Configuration endpoint, specifically affecting the sub_452CCC function in the /boafrm/formWlEncrypt file. The vulnerability can be triggered through manipulation of the submit-url argument, allowing remote attackers to potentially execute arbitrary code or cause denial of service conditions on affected devices.

Critical Impact

Remote attackers can exploit this stack-based buffer overflow to compromise D-Link DWR-M960 routers, potentially gaining full control of the device and any connected network infrastructure.

Affected Products

• D-Link DWR-M960 Firmware version 1.01.07
• D-Link DWR-M960 Hardware revision B1
• D-Link DWR-M960 4G LTE Router

Discovery Timeline

• 2026-02-22 - CVE-2026-2928 published to NVD
• 2026-02-23 - Last updated in NVD database

Technical Details for CVE-2026-2928

Vulnerability Analysis

This vulnerability is classified as CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). The flaw resides in the sub_452CCC function, which handles WLAN encryption configuration requests via the web management interface. When processing the submit-url parameter, the function fails to properly validate the length of user-supplied input before copying it to a stack-based buffer.

The vulnerability can be exploited remotely over the network with low complexity, requiring only low-level privileges to execute. No user interaction is necessary for successful exploitation. A successful attack can result in high impact to confidentiality, integrity, and availability of the affected device.

Root Cause

The root cause of this vulnerability stems from insufficient input validation in the WLAN encryption configuration handler. The sub_452CCC function does not implement proper bounds checking when processing the submit-url parameter, allowing an attacker to supply an oversized input that exceeds the allocated stack buffer. This classic buffer overflow condition enables memory corruption, potentially allowing attackers to overwrite the return address and hijack program execution flow.

Attack Vector

The attack vector for CVE-2026-2928 is network-based, meaning attackers can exploit this vulnerability remotely without physical access to the device. The vulnerable endpoint /boafrm/formWlEncrypt is accessible through the device's web management interface.

An attacker would craft a malicious HTTP request to the WLAN Encryption Configuration endpoint with an oversized submit-url parameter. The overflow occurs when the vulnerable function attempts to process this parameter, copying the malicious payload onto the stack without proper length verification. This can result in arbitrary code execution, device compromise, or denial of service.

The exploit for this vulnerability has been publicly disclosed, increasing the risk of widespread exploitation against unpatched devices. For technical details regarding the vulnerability mechanism, refer to the GitHub Issue Discussion or the VulDB CTI Entry.

Detection Methods for CVE-2026-2928

Indicators of Compromise

• Unexpected HTTP POST requests to /boafrm/formWlEncrypt with abnormally long submit-url parameters
• Router crashes, reboots, or unresponsive web management interface
• Anomalous network traffic originating from or destined to the D-Link DWR-M960 management ports
• Unauthorized configuration changes to WLAN encryption settings

Detection Strategies

• Deploy network intrusion detection rules to identify HTTP requests targeting /boafrm/formWlEncrypt with oversized parameters
• Monitor web server access logs for requests containing unusually long query strings or POST data
• Implement application-layer firewall rules to inspect and block malformed requests to router management interfaces
• Configure SIEM alerts for multiple failed authentication attempts or suspicious access patterns against network infrastructure devices

Monitoring Recommendations

• Enable logging on D-Link DWR-M960 devices and forward logs to a centralized SIEM solution
• Monitor network traffic for anomalous patterns targeting internal network infrastructure
• Regularly audit device configurations for unauthorized changes
• Implement network segmentation to isolate management interfaces from untrusted networks

How to Mitigate CVE-2026-2928

Immediate Actions Required

• Restrict access to the D-Link DWR-M960 web management interface to trusted administrative networks only
• Disable remote management features if not explicitly required
• Implement network-level access controls (firewall rules, ACLs) to block external access to the device management interface
• Monitor for firmware updates from D-Link and apply patches immediately when available

Patch Information

At the time of publication, no official patch information has been released by D-Link for this vulnerability. Organizations should monitor the D-Link Security Resources page for firmware updates addressing CVE-2026-2928. Until a patch is available, implementing the recommended mitigations and workarounds is critical to reducing exposure.

Workarounds

• Disable the web management interface if not required for device administration
• Place the D-Link DWR-M960 behind a firewall that blocks access to management ports from untrusted networks
• Use VPN connectivity to access the management interface when remote administration is necessary
• Consider replacing end-of-life or unsupported devices with current models that receive active security updates

# Example firewall rule to restrict management interface access
# Block external access to router management interface
iptables -A INPUT -i eth0 -p tcp --dport 80 -s ! 192.168.1.0/24 -j DROP
iptables -A INPUT -i eth0 -p tcp --dport 443 -s ! 192.168.1.0/24 -j DROP

# Alternative: Restrict to specific admin workstation
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.100 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP