CVE-2025-70229: D-Link DIR-513 Buffer Overflow Flaw

CVE-2025-70229 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/formSchedule endpoint, where improper handling of the curTime parameter allows an attacker to overflow a stack-based buffer. This memory corruption flaw could potentially allow attackers to execute arbitrary code on vulnerable devices or cause a denial of service condition.

Critical Impact

Attackers may exploit this stack buffer overflow to gain unauthorized control over affected D-Link DIR-513 routers, potentially compromising network security and enabling further attacks on connected devices.

Affected Products

• D-Link DIR-513 firmware version 1.10
• D-Link DIR-513 routers with vulnerable goform/formSchedule endpoint

Discovery Timeline

• 2026-03-05 - CVE CVE-2025-70229 published to NVD
• 2026-03-05 - Last updated in NVD database

Technical Details for CVE-2025-70229

Vulnerability Analysis

This vulnerability is a classic stack buffer overflow affecting embedded router firmware. The goform/formSchedule endpoint in D-Link DIR-513 v1.10 fails to properly validate the length of user-supplied input passed through the curTime parameter before copying it into a fixed-size stack buffer. When an attacker provides input exceeding the expected buffer size, the excess data overwrites adjacent memory on the stack, including potentially critical control data such as saved return addresses and frame pointers.

The exploitation of this vulnerability could allow attackers to hijack program execution flow, enabling arbitrary code execution with the privileges of the web server process running on the router. Given that embedded router firmware typically runs with elevated privileges, successful exploitation may result in complete device compromise.

Root Cause

The root cause of this vulnerability is insufficient input validation and improper bounds checking when processing the curTime parameter in the formSchedule form handler. The firmware does not verify that user-supplied data fits within the allocated stack buffer before performing memory copy operations, creating the conditions necessary for a buffer overflow attack.

Attack Vector

The vulnerability is exploitable through the router's web administration interface. An attacker with network access to the management interface can craft a malicious HTTP POST request to the goform/formSchedule endpoint containing an oversized curTime parameter value. The attack does not require authentication if the management interface is exposed or accessible from the local network.

The exploitation technique involves:

1. Identifying the vulnerable endpoint (goform/formSchedule)
2. Crafting a malicious curTime parameter with payload data exceeding the buffer allocation
3. Submitting the request to trigger the stack buffer overflow
4. Overwriting return addresses or function pointers to redirect execution to attacker-controlled code

For technical details and proof-of-concept information, refer to the GitHub CVE Report.

Detection Methods for CVE-2025-70229

Indicators of Compromise

• Unusual or oversized HTTP POST requests targeting /goform/formSchedule on D-Link DIR-513 devices
• Abnormal router behavior including unexpected reboots or unresponsive web interface
• Suspicious network traffic originating from the router to unknown external destinations
• Unexpected changes to router configuration or firmware

Detection Strategies

• Monitor HTTP traffic to D-Link routers for requests containing abnormally long curTime parameter values
• Implement network intrusion detection rules to identify buffer overflow attack patterns targeting goform/formSchedule
• Deploy SentinelOne Singularity to detect anomalous behavior patterns associated with exploitation attempts
• Regularly audit router access logs for suspicious activity patterns

Monitoring Recommendations

• Restrict management interface access to trusted networks or specific IP addresses only
• Enable logging on the router and forward logs to a centralized SIEM for analysis
• Implement network segmentation to isolate IoT and network infrastructure devices
• Schedule regular vulnerability scans of network infrastructure devices

How to Mitigate CVE-2025-70229

Immediate Actions Required

• Verify if your D-Link DIR-513 router is running firmware version 1.10 and is potentially affected
• Disable remote management access to the router's web interface immediately
• Restrict access to the router administration interface to trusted internal networks only
• Monitor the D-Link Security Bulletin for firmware updates addressing this vulnerability

Patch Information

At the time of publication, no vendor patch has been confirmed. Organizations should monitor D-Link's official security bulletins and the D-Link Product Information page for firmware updates. If the device has reached end-of-life status, consider replacing it with a supported device that receives security updates.

Workarounds

• Disable the web-based management interface if not required for operations
• Place the router behind a firewall that filters incoming HTTP requests to management interfaces
• Implement access control lists (ACLs) to restrict management access to specific administrator IP addresses
• Consider replacing end-of-life devices with currently supported models

# Example: Restrict management interface access (if supported by device)
# Access router CLI or web interface and configure:
# - Disable remote management
# - Enable management access only from specific internal IPs
# - Enable HTTPS for management if available
# Consult D-Link documentation for device-specific configuration commands