CVE-2025-70242 Overview
A stack buffer overflow vulnerability exists in D-Link DIR-513 firmware version 1.10. The vulnerability is triggered via the webPage parameter when processing requests to the goform/formSetWanPPTP endpoint. This flaw allows remote attackers to cause a denial of service condition by sending specially crafted requests to the affected router's web management interface.
Critical Impact
Network-accessible stack buffer overflow in D-Link DIR-513 routers can lead to denial of service, potentially disrupting network connectivity for all connected devices.
Affected Products
- D-Link DIR-513 Firmware version 1.10
- D-Link DIR-513 Hardware
Discovery Timeline
- 2026-03-10 - CVE CVE-2025-70242 published to NVD
- 2026-03-11 - Last updated in NVD database
Technical Details for CVE-2025-70242
Vulnerability Analysis
This vulnerability is classified as CWE-121 (Stack-based Buffer Overflow), a memory corruption flaw that occurs when user-supplied input exceeds the allocated buffer size on the stack. The affected endpoint goform/formSetWanPPTP handles WAN PPTP configuration settings and fails to properly validate the length of the webPage parameter before copying it to a fixed-size stack buffer.
When an attacker submits an oversized value for the webPage parameter, the input overflows the allocated buffer space, corrupting adjacent stack memory. This memory corruption can overwrite critical stack data including return addresses and saved registers, leading to unpredictable behavior and service disruption.
Root Cause
The root cause of this vulnerability is improper input validation in the web form handler for PPTP WAN configuration. The firmware does not implement adequate bounds checking on the webPage parameter before copying user-supplied data into a stack-allocated buffer. This allows attackers to provide input that exceeds the buffer's capacity, resulting in a classic stack buffer overflow condition.
Attack Vector
The vulnerability is exploitable remotely over the network without requiring authentication or user interaction. An attacker can send a malicious HTTP POST request to the goform/formSetWanPPTP endpoint with an oversized webPage parameter value. The attack targets the router's web management interface, which is typically accessible on the local network and potentially exposed to the internet if remote management is enabled.
The exploitation process involves:
- Identifying a vulnerable D-Link DIR-513 router running firmware version 1.10
- Crafting an HTTP POST request to the /goform/formSetWanPPTP endpoint
- Including an excessively long string in the webPage parameter to trigger the overflow
- The overflow corrupts stack memory, causing the web service or device to crash
For detailed technical analysis and proof-of-concept information, refer to the GitHub CVE-Report Repository.
Detection Methods for CVE-2025-70242
Indicators of Compromise
- Unexpected router reboots or web interface unavailability
- Abnormally large HTTP POST requests to /goform/formSetWanPPTP endpoint
- Network logs showing repeated requests with oversized webPage parameter values
- Router crash dumps or system instability reports
Detection Strategies
- Monitor HTTP traffic to router management interfaces for unusually large POST requests
- Implement intrusion detection rules to flag requests containing oversized parameters to formSetWanPPTP
- Configure network monitoring to alert on repeated connection attempts to router web interfaces from unusual sources
- Deploy web application firewall rules to limit parameter sizes for router management endpoints
Monitoring Recommendations
- Enable logging on network firewalls to capture traffic destined for router management ports
- Review router access logs for suspicious POST requests to goform endpoints
- Set up automated alerts for router availability monitoring to detect DoS conditions
- Audit network segmentation to ensure router management interfaces are not exposed to untrusted networks
How to Mitigate CVE-2025-70242
Immediate Actions Required
- Restrict access to the router's web management interface to trusted IP addresses only
- Disable remote management if not required
- Implement network segmentation to isolate router management interfaces from untrusted networks
- Monitor for firmware updates from D-Link and apply patches when available
Patch Information
D-Link has been notified of this vulnerability. Users should monitor the D-Link Security Bulletin page for official patches and security advisories. Until a patch is available, implement the recommended workarounds to reduce exposure.
For additional product information, visit the D-Link Product Information page.
Workarounds
- Configure firewall rules to block external access to the router's web management interface (typically port 80/443)
- Use access control lists (ACLs) to limit management access to specific trusted IP addresses
- Disable WAN-side management access through the router's configuration interface
- Consider replacing end-of-life devices with supported models that receive regular security updates
# Example firewall rule to restrict router management access
# Adjust IP ranges and ports according to your network configuration
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -s 192.168.1.0/24 -j ACCEPT
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.
