CVE-2025-70241 Overview
CVE-2025-70241 is a stack buffer overflow vulnerability affecting the D-Link DIR-513 router running firmware version 1.10. The flaw resides in the goform/formSetWANType_Wizard5 endpoint and is triggered through the curTime parameter. An unauthenticated remote attacker can send a crafted HTTP request to corrupt stack memory, potentially achieving arbitrary code execution on the device. The vulnerability is classified under CWE-787 (Out-of-bounds Write) and CWE-121 (Stack-based Buffer Overflow). The DIR-513 is a legacy consumer router, and exploitation could yield full control of the device for use in botnets, traffic interception, or lateral movement into connected networks.
Critical Impact
Unauthenticated network attackers can trigger a stack-based buffer overflow to execute arbitrary code on affected D-Link DIR-513 routers, compromising confidentiality, integrity, and availability.
Affected Products
- D-Link DIR-513 hardware router
- D-Link DIR-513 firmware version 1.10
- Legacy DIR-513 deployments in residential and small-office environments
Discovery Timeline
- 2026-03-03 - CVE-2025-70241 published to the National Vulnerability Database (NVD)
- 2026-03-09 - Last updated in NVD database
Technical Details for CVE-2025-70241
Vulnerability Analysis
The vulnerability exists in the web management interface of the DIR-513 firmware, specifically within the handler for goform/formSetWANType_Wizard5. This endpoint is part of the WAN configuration wizard exposed by the router's embedded HTTP server. When the handler processes the curTime request parameter, it copies attacker-controlled input into a fixed-size stack buffer without enforcing length validation. Supplying an oversized value overwrites adjacent stack data, including the saved return address. Because the affected router lacks modern exploit mitigations such as stack canaries and address space layout randomization, an attacker can reliably redirect execution to attacker-supplied shellcode or to existing code gadgets.
Root Cause
The root cause is the absence of bounds checking on the curTime parameter before it is written into a stack-allocated buffer. The firmware relies on unsafe string handling routines, characteristic of older MIPS-based D-Link consumer devices, to copy HTTP form data directly into local variables. This pattern matches [CWE-121] stack-based buffer overflow conditions.
Attack Vector
Exploitation requires only network access to the router's web administration interface. No authentication and no user interaction are needed. An attacker sends a single HTTP POST request to /goform/formSetWANType_Wizard5 with an oversized curTime value. If the management interface is reachable from the WAN — a common misconfiguration on legacy consumer devices — the attack is exploitable across the internet. The DIR-513 has reached end-of-service, increasing the likelihood that deployed units remain unpatched. Technical details and a proof-of-concept reproduction can be found in the GitHub CVE Report.
Detection Methods for CVE-2025-70241
Indicators of Compromise
- Inbound HTTP POST requests targeting /goform/formSetWANType_Wizard5 from unexpected source addresses
- Requests containing abnormally long curTime parameter values exceeding typical timestamp lengths
- Unexpected outbound connections originating from the router to unknown command-and-control hosts
- Router crashes, unscheduled reboots, or configuration changes without administrator action
Detection Strategies
- Inspect web server access logs on the device or upstream proxies for requests to the formSetWANType_Wizard5 endpoint
- Deploy network intrusion detection signatures that flag oversized parameter values in router management traffic
- Monitor for HTTP requests to consumer router web interfaces originating from the WAN side
- Correlate router behavioral anomalies with network telemetry to identify post-exploitation activity
Monitoring Recommendations
- Forward network flow data and DNS logs from segments containing the DIR-513 into a centralized analytics platform
- Track changes to router firmware version strings and configuration to identify tampering
- Alert on new administrative sessions or DHCP lease anomalies originating from the router
How to Mitigate CVE-2025-70241
Immediate Actions Required
- Disable remote (WAN-side) management on the DIR-513 web interface immediately
- Restrict LAN-side access to the management interface to a dedicated administrative subnet
- Place the DIR-513 behind an upstream firewall that filters inbound HTTP requests to its management ports
- Plan replacement of the DIR-513 with a supported router, as the device is end-of-life
Patch Information
No vendor patch has been published at the time of NVD listing. The DIR-513 is a legacy product, and remediation guidance is consolidated on the D-Link Security Bulletin page. Administrators should consult the D-Link Product Information page for end-of-service status and replacement recommendations.
Workarounds
- Block external access to TCP ports used by the router's web management interface at the perimeter
- Segment the DIR-513 onto an isolated VLAN with strict egress filtering until replacement
- Disable the WAN configuration wizard pages if the device supports administrative customization
# Example perimeter filter blocking inbound access to the router management interface
iptables -A FORWARD -p tcp -d <router_ip> --dport 80 -j DROP
iptables -A FORWARD -p tcp -d <router_ip> --dport 443 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
