CVE-2025-70249 Overview
A stack buffer overflow vulnerability has been identified in the D-Link DIR-513 router firmware version 1.10. The vulnerability exists in the curTime parameter handling within the goform/formSetWizard2 endpoint. This flaw allows remote attackers to cause a denial of service condition by sending specially crafted HTTP requests to the vulnerable web interface.
Critical Impact
Remote unauthenticated attackers can exploit this stack buffer overflow to crash the device, causing a denial of service condition that disrupts network connectivity for all connected users.
Affected Products
- D-Link DIR-513 Firmware version 1.10
- D-Link DIR-513 Hardware
Discovery Timeline
- 2026-03-10 - CVE-2025-70249 published to NVD
- 2026-03-11 - Last updated in NVD database
Technical Details for CVE-2025-70249
Vulnerability Analysis
This vulnerability is classified as CWE-121: Stack-based Buffer Overflow. The flaw occurs in the web management interface of the D-Link DIR-513 router when processing the curTime parameter submitted to the goform/formSetWizard2 endpoint. The firmware fails to properly validate the length of user-supplied input before copying it to a fixed-size stack buffer, allowing attackers to overflow the buffer and corrupt adjacent memory on the stack.
The attack can be executed remotely over the network without requiring any authentication or user interaction. While the primary confirmed impact is availability loss through denial of service, stack buffer overflows of this nature can potentially be leveraged for more severe attacks depending on the memory layout and protections implemented in the firmware.
Root Cause
The root cause of this vulnerability is improper input validation in the firmware's web server component. When the goform/formSetWizard2 form handler processes the curTime parameter, it copies the user-supplied value directly into a stack-allocated buffer without verifying that the input length does not exceed the buffer's capacity. This classic programming error allows an attacker to supply an oversized value that overwrites the stack frame, corrupting return addresses and other critical data structures.
Attack Vector
The vulnerability is exploitable via network-based attacks targeting the router's web management interface. An attacker can send a malicious HTTP POST request to the goform/formSetWizard2 endpoint with an oversized curTime parameter value. Since no authentication is required to reach this endpoint, any attacker with network access to the router's management interface can trigger the overflow.
The attack scenario involves sending a crafted HTTP request containing an excessively long string in the curTime parameter. When the vulnerable firmware processes this request, the oversized input overflows the stack buffer, corrupting stack memory and causing the device to crash or become unresponsive. For technical details on the vulnerability, refer to the GitHub CVE-2025-70249 Report.
Detection Methods for CVE-2025-70249
Indicators of Compromise
- Unexpected router reboots or crashes, particularly following web interface access attempts
- Abnormally large HTTP POST requests targeting /goform/formSetWizard2 in router logs
- Network connectivity disruptions coinciding with suspicious traffic to the router's management port
- Error logs indicating memory corruption or stack smashing in device diagnostics
Detection Strategies
- Monitor network traffic for HTTP POST requests to goform/formSetWizard2 containing unusually long parameter values
- Implement intrusion detection rules to flag requests with curTime parameters exceeding expected length thresholds
- Deploy network-based anomaly detection to identify patterns consistent with buffer overflow exploitation attempts
- Configure alerting for repeated connection attempts to the router management interface from untrusted sources
Monitoring Recommendations
- Enable logging on the D-Link DIR-513 web management interface and review logs regularly for suspicious activity
- Monitor router uptime and availability metrics to detect unexpected restarts that may indicate exploitation
- Implement network segmentation to restrict access to the router's management interface to trusted administrative hosts only
How to Mitigate CVE-2025-70249
Immediate Actions Required
- Restrict access to the router's web management interface to trusted internal networks only
- Disable remote management if it is enabled and not required for operations
- Implement firewall rules to block external access to the router's administrative ports
- Monitor the D-Link Security Bulletin for firmware updates addressing this vulnerability
Patch Information
As of the last update, check the D-Link Security Bulletin for the latest security patches and firmware updates for the DIR-513. Review the D-Link Product Info Page for supported firmware versions and upgrade instructions.
Workarounds
- Disable the web management interface entirely if administrative access is not frequently required
- Configure access control lists (ACLs) to limit management interface access to specific trusted IP addresses
- Place the router behind a firewall that filters incoming requests to management endpoints
- Consider replacing end-of-life devices with newer models that receive regular security updates
# Example firewall rule to restrict management interface access (adjust for your environment)
# Block external access to router management port (typically port 80 or 8080)
iptables -A FORWARD -d <ROUTER_IP> -p tcp --dport 80 -j DROP
iptables -A FORWARD -d <ROUTER_IP> -p tcp --dport 8080 -j DROP
# Allow management access only from trusted admin workstation
iptables -I FORWARD -s <ADMIN_IP> -d <ROUTER_IP> -p tcp --dport 80 -j ACCEPT
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
