CVE-2025-6486 Overview
CVE-2025-6486 is a stack-based buffer overflow in the TOTOLINK A3002R router firmware version 1.1.1-B20200824.0128. The flaw resides in the formWlanMultipleAP function within the /boafrm/formWlanMultipleAP endpoint. Attackers can exploit the vulnerability by manipulating the submit-url argument over the network. The weakness maps to [CWE-119] (improper restriction of operations within the bounds of a memory buffer) and can lead to memory corruption and arbitrary code execution on the affected device. Public disclosure of the exploit technique increases the risk of opportunistic attacks against exposed devices.
Critical Impact
Remote attackers with low-level privileges can trigger a stack-based buffer overflow against the router's web management interface, potentially executing arbitrary code and gaining persistent control of the device.
Affected Products
- TOTOLINK A3002R router (hardware)
- TOTOLINK A3002R firmware version 1.1.1-B20200824.0128
- Deployments exposing the /boafrm/formWlanMultipleAP endpoint to untrusted networks
Discovery Timeline
- 2025-06-22 - CVE-2025-6486 published to the National Vulnerability Database (NVD)
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-6486
Vulnerability Analysis
The vulnerability lives in the formWlanMultipleAP handler exposed through the /boafrm/formWlanMultipleAP URI on the embedded boa-based web server. The handler reads the submit-url HTTP parameter and copies it into a fixed-size stack buffer without validating the input length. Sending an oversized value overwrites adjacent stack memory, including saved return addresses, which allows attackers to redirect execution flow.
Authenticated network attackers can deliver the malicious request directly to the router's management interface. Successful exploitation results in full compromise of confidentiality, integrity, and availability on the device. Because the A3002R runs the web service with elevated privileges, code execution typically yields root-level control of the router. According to public scoring data, the EPSS probability is 0.759% at the 50.42 percentile, indicating measurable but not yet widespread exploitation activity.
Root Cause
The firmware fails to enforce bounds checking when handling the submit-url parameter inside formWlanMultipleAP. Standard library copy operations such as strcpy or sprintf write attacker-controlled data into a stack buffer of insufficient size. This violates the secure coding requirements described in [CWE-119].
Attack Vector
An attacker sends a crafted HTTP POST request to /boafrm/formWlanMultipleAP with an overlong submit-url value. The request reaches the vulnerable handler, overflows the stack buffer, and overwrites the saved return address. The attack requires network reachability to the management interface and low-level credentials. Detailed reproduction steps are documented in the GitHub Vulnerability Documentation and the VulDB entry #313594.
No verified public exploit code has been incorporated here; refer to the linked advisories for technical reproduction details.
Detection Methods for CVE-2025-6486
Indicators of Compromise
- HTTP POST requests to /boafrm/formWlanMultipleAP containing abnormally long submit-url parameter values
- Unexpected reboots, crashes, or httpd/boa process restarts on the TOTOLINK A3002R router
- Outbound connections from the router to unfamiliar IP addresses after web interface activity
- New or unexpected configuration changes to wireless multiple AP settings
Detection Strategies
- Inspect web server and reverse proxy logs for POST requests to /boafrm/formWlanMultipleAP with Content-Length values that exceed normal form submissions
- Apply network intrusion detection signatures that flag oversized submit-url form fields targeting boa-based embedded web servers
- Correlate router management traffic with source addresses outside the expected administrative subnet
Monitoring Recommendations
- Capture and retain HTTP traffic to router management interfaces for forensic review
- Alert on repeated authentication attempts followed by POST requests to wireless configuration endpoints
- Monitor router uptime and service health metrics for anomalies that suggest crash-and-restart patterns
How to Mitigate CVE-2025-6486
Immediate Actions Required
- Restrict access to the router's web management interface to trusted administrative networks only, and disable WAN-side management
- Change default and shared administrative credentials to reduce the chance of an attacker meeting the low privilege requirement
- Audit deployed TOTOLINK A3002R devices and inventory those running firmware 1.1.1-B20200824.0128
- Place vulnerable devices behind a firewall or VLAN that blocks untrusted HTTP traffic to /boafrm/formWlanMultipleAP
Patch Information
No vendor patch has been published in the available references. Consult the TOTOLINK Official Website for firmware updates and confirm version status before redeployment. If a fixed firmware release becomes available, apply it across all affected devices.
Workarounds
- Disable the wireless Multiple AP feature when it is not required so the vulnerable handler is not exercised
- Use ACLs on upstream network equipment to block external access to TCP ports hosting the router web interface
- Replace end-of-support or unpatched A3002R devices with hardware that receives active security maintenance
# Example: restrict router management interface to a trusted subnet
# Replace 192.0.2.0/24 with your administrative network
iptables -A INPUT -p tcp --dport 80 -s 192.0.2.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -s 192.0.2.0/24 -j ACCEPT
iptables -A INPUT -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.
