CVE-2025-70219 Overview
A stack buffer overflow vulnerability has been identified in D-Link DIR-513 router firmware version 1.10. The vulnerability exists in the goform/formDeviceReboot endpoint, which fails to properly validate user-supplied input before copying it to a fixed-size stack buffer. This allows a remote attacker to overwrite adjacent memory on the stack, potentially leading to arbitrary code execution with root privileges on the affected device.
Critical Impact
This vulnerability enables unauthenticated remote code execution on affected D-Link DIR-513 routers, allowing complete device compromise including network traffic interception, firmware modification, and lateral movement within the network.
Affected Products
- D-Link DIR-513 firmware version 1.10
- D-Link DIR-513 routers running vulnerable firmware versions
Discovery Timeline
- 2026-03-04 - CVE-2025-70219 published to NVD
- 2026-03-05 - Last updated in NVD database
Technical Details for CVE-2025-70219
Vulnerability Analysis
This vulnerability is classified as CWE-121 (Stack-based Buffer Overflow), a memory corruption flaw that occurs when user-controlled data exceeds the boundaries of a fixed-size buffer allocated on the stack. The goform/formDeviceReboot endpoint in the D-Link DIR-513 router's web management interface processes HTTP requests without adequate bounds checking on input parameters.
When an attacker sends a specially crafted request to this endpoint with an oversized payload, the vulnerable code copies this data into a stack buffer without verifying its length. This overwrites adjacent stack memory, including saved return addresses and function pointers. By carefully crafting the overflow payload, an attacker can redirect program execution to attacker-controlled code.
The exploitation of this vulnerability requires no authentication, as the affected endpoint is accessible to any network-connected client. Given that consumer routers typically operate with elevated privileges and lack modern exploit mitigations such as ASLR or stack canaries, successful exploitation often results in full device compromise.
Root Cause
The root cause is insufficient input validation in the formDeviceReboot handler function. The code accepts user-supplied parameters from HTTP POST requests and copies them directly to stack-allocated buffers using unsafe string operations (likely strcpy or sprintf) without verifying that the input length does not exceed the buffer capacity. This allows an attacker to provide input exceeding the expected size, triggering the buffer overflow condition.
Attack Vector
The attack is network-based and can be executed remotely without authentication. An attacker with network access to the router's web management interface can exploit this vulnerability by sending a malicious HTTP POST request to the /goform/formDeviceReboot endpoint. The attack requires no user interaction and can be automated for mass exploitation of vulnerable devices exposed to the internet.
The exploitation sequence typically involves:
- Identifying a vulnerable D-Link DIR-513 device via network scanning
- Crafting a malicious POST request with an oversized parameter value
- Sending the request to overflow the stack buffer and overwrite the return address
- Redirecting execution to attacker-supplied shellcode or ROP chain
For technical details regarding the vulnerability mechanism, refer to the GitHub CVE Report Repository.
Detection Methods for CVE-2025-70219
Indicators of Compromise
- Unexpected outbound connections from the router to unknown IP addresses
- Unusual CPU or memory utilization on the affected device
- Modified firmware or configuration files on the router
- Network traffic anomalies such as DNS hijacking or traffic redirection
- Crash logs or unexpected reboots of the router
Detection Strategies
- Monitor HTTP traffic to router management interfaces for abnormally large POST requests to /goform/formDeviceReboot
- Implement network-based intrusion detection rules to alert on oversized parameters in requests to D-Link web interfaces
- Deploy honeypots mimicking vulnerable D-Link devices to detect active exploitation attempts
- Analyze router logs for repeated access attempts to the vulnerable endpoint
Monitoring Recommendations
- Enable logging on the router if supported and forward logs to a centralized SIEM
- Monitor network traffic for suspicious patterns targeting port 80/443 on router IP addresses
- Implement network segmentation to isolate IoT and network devices from critical infrastructure
- Regularly audit firmware versions across all network devices to identify vulnerable installations
How to Mitigate CVE-2025-70219
Immediate Actions Required
- Disable remote management access to the router's web interface immediately
- Restrict access to the router's management interface to trusted IP addresses only
- Place the router behind a firewall that blocks external access to management ports
- Check for unauthorized configuration changes or firmware modifications
- Consider replacing end-of-life devices with currently supported models
Patch Information
At the time of publication, users should consult the D-Link Security Bulletin for official patch availability and firmware updates. Additionally, refer to the D-Link Product Information page for support status and available downloads.
Given that the DIR-513 may be an end-of-life product, D-Link may not provide security patches. Users of unsupported devices should prioritize device replacement with actively maintained alternatives.
Workarounds
- Disable the web-based management interface entirely if not required
- Configure firewall rules to block all external access to TCP ports 80 and 443 on the router
- Enable MAC address filtering to restrict management interface access
- Use VPN to access the router's management interface instead of direct network exposure
- Monitor the device for signs of compromise and prepare for device replacement
# Example firewall rule to block external access to router management (iptables)
# Apply on upstream firewall or gateway device
iptables -A FORWARD -d <ROUTER_IP> -p tcp --dport 80 -j DROP
iptables -A FORWARD -d <ROUTER_IP> -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.
