CVE-2026-2883 Overview
A stack-based buffer overflow vulnerability has been identified in D-Link DWR-M960 firmware version 1.01.07. The vulnerability exists in the function sub_427D74 within the file /boafrm/formIpQoS, where improper handling of the submit-url argument allows an attacker to trigger a buffer overflow condition. This vulnerability can be exploited remotely over the network, potentially allowing attackers to execute arbitrary code or cause denial of service on affected devices. The exploit has been publicly disclosed and may be actively utilized by threat actors.
Critical Impact
Remote attackers with low-level privileges can exploit this stack-based buffer overflow to potentially achieve code execution on D-Link DWR-M960 routers, compromising network security and enabling further lateral movement.
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
- 2026-02-21 - CVE-2026-2883 published to NVD
- 2026-02-23 - Last updated in NVD database
Technical Details for CVE-2026-2883
Vulnerability Analysis
This vulnerability is classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). The affected function sub_427D74 in the /boafrm/formIpQoS endpoint fails to properly validate the length of user-supplied input passed through the submit-url parameter before copying it into a fixed-size stack buffer.
When an attacker sends a specially crafted HTTP request with an oversized submit-url value, the application copies this data without proper bounds checking. This overwrites adjacent memory on the stack, including saved return addresses and other critical control data. In embedded devices like the DWR-M960, which typically lack modern exploit mitigations such as ASLR or stack canaries, this type of vulnerability is particularly dangerous as it provides a reliable path to code execution.
The network-accessible nature of this endpoint, combined with the low privilege requirement for exploitation, makes this a significant risk for any organization deploying these devices in production environments.
Root Cause
The root cause of this vulnerability is insufficient input validation in the sub_427D74 function. The firmware fails to verify that the length of the submit-url parameter does not exceed the allocated buffer size on the stack. This is a classic memory safety issue common in C/C++ based embedded firmware where manual memory management is required. The vulnerable code likely uses an unsafe string copy function (such as strcpy or sprintf) without first checking the input length against buffer capacity.
Attack Vector
The attack vector for CVE-2026-2883 is network-based, allowing remote exploitation. An authenticated attacker with network access to the device's web management interface can exploit this vulnerability by:
- Sending an HTTP POST request to the /boafrm/formIpQoS endpoint
- Including a maliciously crafted submit-url parameter that exceeds expected buffer boundaries
- The oversized input triggers a stack-based buffer overflow in sub_427D74
- Carefully crafted payloads can overwrite the return address to redirect execution flow
- Successful exploitation can result in arbitrary code execution with the privileges of the web server process
The vulnerability can be exploited after authentication, requiring low-level privileges to access the affected endpoint. For detailed technical information, refer to the GitHub Issue Discussion and VulDB entry #347177.
Detection Methods for CVE-2026-2883
Indicators of Compromise
- Unusual HTTP POST requests to /boafrm/formIpQoS containing abnormally long submit-url parameter values
- Unexpected device reboots or service crashes on D-Link DWR-M960 routers
- Anomalous outbound network connections from the router to unknown external IP addresses
- Device configuration changes or new administrative accounts appearing without authorization
Detection Strategies
- Implement IDS/IPS rules to detect HTTP requests with oversized submit-url parameters targeting /boafrm/formIpQoS
- Monitor web server logs on affected devices for repeated requests to the vulnerable endpoint
- Deploy network traffic analysis to identify potential exploitation attempts based on payload size anomalies
- Use firmware integrity monitoring to detect unauthorized modifications to device firmware
Monitoring Recommendations
- Enable detailed logging on D-Link devices where possible and forward logs to a centralized SIEM
- Implement network segmentation to isolate IoT and network infrastructure devices from general network traffic
- Regularly review access logs for the device management interface for suspicious authentication patterns
- Configure alerting for any unexpected device behavior or connectivity patterns
How to Mitigate CVE-2026-2883
Immediate Actions Required
- Restrict network access to the DWR-M960 management interface to trusted administrative networks only
- Implement firewall rules to block external access to the device's web interface on ports 80 and 443
- Consider disabling remote management features until a patch is available
- Monitor for firmware updates from D-Link and apply patches immediately upon release
Patch Information
As of the last modification date (2026-02-23), no official patch has been released by D-Link for this vulnerability. Organizations should monitor the D-Link Security Information page for security advisories and firmware updates. Given D-Link's history with end-of-life products, users should verify whether the DWR-M960 is still receiving security support and consider device replacement if no patches are forthcoming.
Workarounds
- Restrict access to the management interface by configuring ACLs to only allow connections from specific trusted IP addresses
- Place the device behind a VPN so that management access requires VPN authentication first
- Disable the web-based management interface entirely if command-line administration is available and sufficient
- Implement a Web Application Firewall (WAF) rule to filter requests with abnormally long submit-url parameters
# Example iptables rule to restrict management interface access
# Only allow access from trusted management network 192.168.1.0/24
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
