CVE-2026-7289: D-Link DIR-825M Buffer Overflow Vulnerability

CVE-2026-7289 Overview

A buffer overflow vulnerability has been discovered in D-Link DIR-825M firmware version 1.1.12. This issue affects the function sub_414BA8 within the file /boafrm/formWanConfigSetup. The vulnerability arises from improper handling of the submit-url argument, which can be manipulated to trigger a buffer overflow condition. As a network-accessible vulnerability, remote attackers can potentially exploit this flaw to compromise affected devices.

Critical Impact

Remote attackers can exploit this buffer overflow vulnerability to potentially execute arbitrary code or cause denial of service on affected D-Link DIR-825M routers running firmware version 1.1.12.

Affected Products

• D-Link DIR-825M firmware version 1.1.12
• D-Link DIR-825M hardware devices

Discovery Timeline

• 2026-04-28 - CVE-2026-7289 published to NVD
• 2026-04-30 - Last updated in NVD database

Technical Details for CVE-2026-7289

Vulnerability Analysis

This vulnerability is classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). The flaw exists in the sub_414BA8 function, which processes user-supplied input from the submit-url parameter in the WAN configuration setup form. When an attacker provides a maliciously crafted value for this parameter, the function fails to properly validate the input length before copying data into a fixed-size buffer, resulting in a buffer overflow condition.

The network-accessible nature of this vulnerability means that attackers do not require physical access to the device. Authentication is required (low privilege level), but once authenticated, exploitation can occur without user interaction. The vulnerability has the potential to compromise the confidentiality, integrity, and availability of the affected device.

Root Cause

The root cause of this vulnerability lies in insufficient input validation within the sub_414BA8 function. The function processes the submit-url argument without adequately checking the length of the input data against the allocated buffer size. This classic buffer overflow condition allows attackers to write beyond the intended memory boundaries, potentially overwriting critical data structures or return addresses.

Attack Vector

The attack vector for CVE-2026-7289 is network-based. An authenticated attacker can send a specially crafted HTTP request to the /boafrm/formWanConfigSetup endpoint on the affected D-Link DIR-825M router. By manipulating the submit-url parameter with an oversized value, the attacker can trigger the buffer overflow in the sub_414BA8 function.

The exploitation technique involves sending a request with a submit-url parameter containing data that exceeds the expected buffer size. This overflow can corrupt adjacent memory, potentially allowing the attacker to control program execution flow or cause the device to become unresponsive. According to VulDB, the exploit technique has been publicly disclosed. For additional technical details, refer to the GitHub Issue Discussion and the VulDB Vulnerability Details.

Detection Methods for CVE-2026-7289

Indicators of Compromise

• Unusual HTTP POST requests targeting /boafrm/formWanConfigSetup with abnormally large submit-url parameter values
• Router instability, unexpected reboots, or unresponsive web management interface
• Unexpected network traffic patterns originating from the router to external IP addresses
• Modified router configurations or unauthorized changes to WAN settings

Detection Strategies

• Implement network monitoring rules to detect HTTP requests with oversized parameters targeting the /boafrm/formWanConfigSetup endpoint
• Deploy intrusion detection/prevention systems (IDS/IPS) with signatures for buffer overflow patterns in D-Link router traffic
• Monitor for firmware version 1.1.12 on D-Link DIR-825M devices during vulnerability assessments
• Review router logs for authentication attempts followed by unusual configuration change requests

Monitoring Recommendations

• Enable logging on D-Link routers and forward logs to a centralized SIEM for analysis
• Implement network segmentation to isolate IoT devices like routers from critical network segments
• Regularly audit network traffic to and from router management interfaces
• Set up alerts for any access to WAN configuration endpoints from unexpected source addresses

How to Mitigate CVE-2026-7289

Immediate Actions Required

• Restrict access to the router's web management interface to trusted internal networks only
• Disable remote management features if not required for operations
• Implement network segmentation to limit exposure of vulnerable devices
• Monitor for any exploitation attempts using IDS/IPS solutions
• Check the D-Link Security Portal for firmware updates addressing this vulnerability

Patch Information

At the time of publication, no official patch has been confirmed for this vulnerability. Organizations should monitor D-Link's official security advisories for firmware updates that address CVE-2026-7289. Additional vulnerability information can be found at the VulDB Submission Report and VulDB CTI Information.

Workarounds

• Restrict management interface access using firewall rules or access control lists (ACLs)
• Disable WAN-side management access to prevent remote exploitation
• Implement strong authentication and change default credentials
• Consider replacing end-of-life or unsupported devices with newer, actively maintained models

# Example firewall rule to restrict management interface access
# Block external access to router management port (adjust port as needed)
iptables -A INPUT -p tcp --dport 80 -s ! 192.168.1.0/24 -j DROP
iptables -A INPUT -p tcp --dport 443 -s ! 192.168.1.0/24 -j DROP

# Allow management access only from specific trusted IP
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.100 -j ACCEPT