CVE-2025-70246 Overview
A stack buffer overflow vulnerability has been identified in D-Link DIR-513 firmware version 1.10. The vulnerability exists in the goform/formVirtualServ endpoint, where the curTime parameter is improperly handled, allowing an attacker to overflow a stack buffer. This network-accessible vulnerability can be exploited without authentication, making it a significant threat to affected devices deployed in home and small office environments.
Critical Impact
Remote attackers can trigger a denial of service condition by sending specially crafted requests to the vulnerable endpoint, potentially crashing the device and disrupting network connectivity.
Affected Products
- D-Link DIR-513 Firmware version 1.10
- D-Link DIR-513 Hardware Device
Discovery Timeline
- 2026-03-10 - CVE-2025-70246 published to NVD
- 2026-03-11 - Last updated in NVD database
Technical Details for CVE-2025-70246
Vulnerability Analysis
This vulnerability is classified as CWE-121 (Stack-based Buffer Overflow), a memory corruption issue that occurs when data is written beyond the allocated boundaries of a stack buffer. The vulnerable component is the web management interface of the D-Link DIR-513 router, specifically the goform/formVirtualServ handler.
When processing the curTime parameter, the firmware fails to properly validate the input length before copying it into a fixed-size stack buffer. This lack of boundary checking allows attackers to supply an overly long value that overwrites adjacent stack memory, including potentially critical control data such as return addresses or saved frame pointers.
The attack surface is exposed over the network through the router's administrative web interface, requiring no authentication to reach the vulnerable endpoint. This significantly lowers the barrier for exploitation.
Root Cause
The root cause is insufficient input validation in the firmware's form processing code. The curTime parameter is copied into a stack-allocated buffer without verifying that the input length does not exceed the buffer's capacity. This is a classic stack buffer overflow pattern commonly found in embedded systems with limited security controls.
Attack Vector
The vulnerability is exploitable remotely over the network (AV:N) with low attack complexity (AC:L). An attacker can craft a malicious HTTP request to the goform/formVirtualServ endpoint containing an oversized curTime parameter value. When the vulnerable router processes this request, the stack buffer overflow is triggered.
A typical attack would involve:
- Identifying a D-Link DIR-513 device running firmware version 1.10
- Sending an HTTP POST request to /goform/formVirtualServ with a curTime parameter containing a payload that exceeds the expected buffer size
- The overflow corrupts stack memory, leading to a crash and denial of service
For detailed technical analysis and proof of concept information, refer to the GitHub CVE Report for D-Link.
Detection Methods for CVE-2025-70246
Indicators of Compromise
- Unexpected router reboots or unresponsive web management interface
- Abnormally large HTTP POST requests targeting /goform/formVirtualServ
- Network traffic containing oversized curTime parameter values in form submissions
- Device crash logs showing stack corruption or memory access violations
Detection Strategies
- Monitor HTTP traffic to D-Link routers for POST requests to /goform/formVirtualServ with abnormally large parameter values
- Implement network intrusion detection rules to flag requests with curTime parameters exceeding typical length thresholds
- Deploy endpoint detection solutions capable of monitoring embedded device behavior for anomalies
- Use SentinelOne Singularity to detect network-based exploitation attempts targeting IoT devices
Monitoring Recommendations
- Enable logging on network perimeter devices to capture traffic directed at internal IoT devices
- Segment IoT devices including routers on separate network VLANs with restricted access
- Regularly review device uptime and stability metrics to identify potential exploitation attempts
How to Mitigate CVE-2025-70246
Immediate Actions Required
- Check if your D-Link DIR-513 is running firmware version 1.10 and prioritize remediation
- Restrict access to the router's web management interface to trusted internal networks only
- Disable remote management if enabled, limiting exposure to external attackers
- Monitor the D-Link Security Bulletin for official patches and advisories
Patch Information
As of the last update, consult the D-Link Security Bulletin for the latest firmware updates addressing this vulnerability. Organizations should apply vendor-provided patches as soon as they become available. For product-specific information, refer to the D-Link Product Information page.
Workarounds
- Disable the web management interface if not required for daily operations
- Place the router behind a firewall that filters traffic to the /goform/ path
- Implement access control lists (ACLs) to restrict management interface access to specific trusted IP addresses
- Consider replacing end-of-life devices with actively supported hardware
# Example: Restrict management access via firewall rules
# Block external access to router management interface
iptables -A INPUT -p tcp --dport 80 -s ! 192.168.1.0/24 -j DROP
iptables -A INPUT -p tcp --dport 443 -s ! 192.168.1.0/24 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
