CVE-2025-70244: D-Link DIR-513 Buffer Overflow Vulnerability

CVE-2025-70244 Overview

A stack buffer overflow vulnerability has been identified in D-Link DIR-513 firmware version 1.10. The vulnerability exists in the web management interface and can be triggered via the webPage parameter when submitting requests to the goform/formWlanSetup endpoint. This memory corruption flaw allows remote attackers to cause a denial of service condition by sending specially crafted HTTP requests to the vulnerable router.

Critical Impact

Remote unauthenticated attackers can exploit this stack buffer overflow to crash the device, causing network disruption for all connected users. The D-Link DIR-513 is a consumer-grade wireless router, and successful exploitation could leave home and small business networks without connectivity.

Affected Products

• D-Link DIR-513 Firmware version 1.10
• D-Link DIR-513 Hardware (all revisions running vulnerable firmware)

Discovery Timeline

• 2026-03-10 - CVE-2025-70244 published to NVD
• 2026-03-11 - Last updated in NVD database

Technical Details for CVE-2025-70244

Vulnerability Analysis

This vulnerability is classified as CWE-121 (Stack-based Buffer Overflow), a critical memory corruption issue that occurs when data written to a buffer exceeds its allocated size on the stack. In the D-Link DIR-513 router, the web server component fails to properly validate the length of the webPage parameter before copying it to a fixed-size stack buffer during WLAN configuration operations.

The vulnerability is accessible over the network without requiring authentication, making it particularly dangerous for internet-exposed devices or those accessible from untrusted network segments. While the primary impact is denial of service through device crashes, stack buffer overflows can potentially lead to more severe consequences depending on the target architecture and memory protections in place.

Root Cause

The root cause of this vulnerability lies in improper input validation within the goform/formWlanSetup handler. When processing the webPage parameter, the firmware uses unsafe string copy operations without verifying that the input data fits within the allocated stack buffer. This oversight allows an attacker to overwrite adjacent memory on the stack, corrupting return addresses and other critical data structures, ultimately causing the device to crash or behave unpredictably.

Attack Vector

The attack can be executed remotely over the network by any attacker who can reach the device's web management interface. The exploitation requires:

1. Network access to the D-Link DIR-513 router's web interface (typically port 80)
2. Crafting an HTTP POST request to /goform/formWlanSetup with an oversized webPage parameter
3. The malicious payload overwrites stack memory, causing the device to crash

The vulnerability does not require authentication, and no user interaction is needed for successful exploitation. An attacker with network access can repeatedly trigger the flaw to maintain a denial of service condition against the target device.

The vulnerability mechanism involves sending an HTTP POST request to the WLAN setup form handler with an excessively long webPage parameter value. When the router's web server processes this request, it copies the parameter value into a stack-allocated buffer without proper bounds checking, resulting in a stack buffer overflow. For detailed technical analysis, refer to the GitHub CVE Report for D-Link.

Detection Methods for CVE-2025-70244

Indicators of Compromise

• Unexpected router reboots or crashes, particularly when accessing the web management interface
• HTTP POST requests to /goform/formWlanSetup containing unusually large webPage parameter values
• Network logs showing repeated connections to the router's web interface from unknown sources
• Device becoming unresponsive to management connections following suspicious network activity

Detection Strategies

• Monitor network traffic for HTTP POST requests to /goform/formWlanSetup endpoints containing parameters exceeding normal length thresholds
• Implement intrusion detection rules to alert on large payload submissions to D-Link router management interfaces
• Deploy network-based anomaly detection to identify repeated crash/reboot patterns from router devices
• Review web server access logs on upstream devices for suspicious requests targeting vulnerable endpoints

Monitoring Recommendations

• Enable logging on network firewalls and IDS/IPS systems for traffic destined to D-Link router management ports
• Configure SNMP monitoring to detect unexpected device reboots or availability issues
• Implement network segmentation to isolate IoT and router management interfaces from untrusted networks
• Consider deploying SentinelOne Singularity for network visibility to detect exploitation attempts and anomalous device behavior

How to Mitigate CVE-2025-70244

Immediate Actions Required

• Restrict access to the router's web management interface to trusted IP addresses only
• Disable remote management if enabled and not required for operations
• Place the router behind a firewall that blocks external access to the management interface
• Monitor the D-Link Security Bulletin for firmware updates addressing this vulnerability
• Consider replacing the device if it has reached end-of-life status and no patch is available

Patch Information

As of the last update to this vulnerability record, users should check the D-Link Security Bulletin for available firmware updates. D-Link periodically releases security patches for supported products. Device owners should verify whether the DIR-513 is still within its support lifecycle and eligible for security updates.

If no patch is available, D-Link may have classified this device as end-of-life, in which case replacement with a currently supported model is recommended.

Workarounds

• Configure firewall rules to block external access to the router's web management interface (typically TCP port 80)
• Enable management access only from specific trusted internal IP addresses if the router supports access control lists
• Disable the web management interface entirely if device configuration can be managed through other means
• Implement network segmentation to prevent untrusted devices from reaching the router's management interface
• Use a VPN for remote administration needs rather than exposing the management interface directly

# Example firewall rule to restrict management access (iptables on upstream device)
# Block external access to router management interface
iptables -A FORWARD -d 192.168.0.1 -p tcp --dport 80 -j DROP
iptables -A FORWARD -s 192.168.0.0/24 -d 192.168.0.1 -p tcp --dport 80 -j ACCEPT