CVE-2025-70250 Overview
CVE-2025-70250 is a stack buffer overflow vulnerability affecting the D-Link DIR-513 router running firmware version 1.10. The flaw resides in the goform/formdumpeasysetup handler, which fails to validate the length of the curTime parameter before copying it into a fixed-size stack buffer. A remote, unauthenticated attacker can send a crafted HTTP request to trigger memory corruption, resulting in a denial of service. The issue is classified under CWE-121 (Stack-based Buffer Overflow).
Critical Impact
Unauthenticated network attackers can crash the device through a malformed curTime parameter, disrupting router availability for all connected clients.
Affected Products
- D-Link DIR-513 hardware router
- D-Link DIR-513 firmware version 1.10
- Deployments using goform/formdumpeasysetup web interface
Discovery Timeline
- 2026-03-09 - CVE-2025-70250 published to the National Vulnerability Database
- 2026-03-11 - Last updated in NVD database
Technical Details for CVE-2025-70250
Vulnerability Analysis
The DIR-513 web management interface exposes a CGI-style endpoint at goform/formdumpeasysetup that processes setup parameters submitted by the user. The curTime parameter is read from the HTTP request and copied into a fixed-size stack buffer without bounds checking. When the supplied value exceeds the buffer capacity, adjacent stack memory is overwritten, corrupting saved registers and the return address.
The DIR-513 is a legacy consumer router that has reached end-of-life status. D-Link historically recommends retirement rather than patching for products in this category, increasing exposure for users who continue to operate the device. Successful exploitation interrupts network connectivity for downstream clients and forces a manual reboot to restore service.
Root Cause
The root cause is missing input length validation in the handler responsible for parsing the curTime HTTP parameter. The code uses an unbounded string copy operation, such as strcpy or sprintf, into a stack-allocated buffer. This pattern, classified as [CWE-121], is common in embedded web servers compiled from BusyBox or vendor-specific goform frameworks where developer-supplied length checks are absent.
Attack Vector
Exploitation requires only network reachability to the router's HTTP management interface. No authentication or user interaction is needed. An attacker sends an HTTP POST or GET request to goform/formdumpeasysetup with an oversized curTime value. The malformed input overflows the stack buffer and crashes the httpd process or the entire device. Refer to the GitHub CVE Report for the technical write-up.
Detection Methods for CVE-2025-70250
Indicators of Compromise
- HTTP requests to goform/formdumpeasysetup containing abnormally long curTime parameter values
- Repeated router reboots or httpd process crashes following inbound HTTP traffic
- Loss of LAN or WAN connectivity correlated with management interface access from untrusted sources
Detection Strategies
- Inspect web server access logs on the router for requests targeting formdumpeasysetup with parameter lengths exceeding typical timestamp values
- Deploy network intrusion detection signatures that flag oversized curTime parameters in HTTP traffic destined for D-Link management interfaces
- Monitor for unexpected HTTP traffic to router management ports originating from the WAN side
Monitoring Recommendations
- Alert on any external access attempts to the router administration interface, especially TCP/80 and TCP/443 from the WAN
- Track router uptime metrics through SNMP or syslog to identify abnormal reboot patterns
- Capture full-packet HTTP traffic to embedded devices for forensic analysis when crashes occur
How to Mitigate CVE-2025-70250
Immediate Actions Required
- Disable remote (WAN-side) administration on the DIR-513 to prevent unauthenticated network exploitation
- Restrict LAN access to the management interface using firewall rules or VLAN segmentation
- Replace the DIR-513 with a currently supported router model, as the device is at end-of-life
Patch Information
No security patch is currently listed for the DIR-513 firmware version 1.10. Consult the D-Link Security Bulletin for vendor announcements. For end-of-life devices, D-Link typically advises hardware replacement rather than issuing firmware updates. Review D-Link Product Information for product lifecycle status.
Workarounds
- Block inbound HTTP and HTTPS traffic to the router management interface at the upstream firewall
- Place the DIR-513 behind a network segment that restricts access to trusted administrative hosts only
- Disable the easysetup web functionality if the device configuration permits
# Example iptables rule to block WAN-side management access
iptables -A INPUT -i eth0 -p tcp --dport 80 -j DROP
iptables -A INPUT -i eth0 -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.
