CVE-2025-4824 Overview
CVE-2025-4824 is a buffer overflow vulnerability affecting TOTOLINK A702R, A3002R, and A3002RU routers running firmware version 3.0.0-B20230809.1615. The flaw resides in the HTTP POST request handler at /boafrm/formWsc, where the submit-url argument is processed without proper bounds checking. Attackers can exploit this issue remotely over the network to corrupt memory on the device. Public disclosure of the exploit details increases the risk of opportunistic attacks against exposed devices. The vulnerability is tracked under [CWE-119] and [CWE-120], covering improper restriction of operations within memory buffer bounds.
Critical Impact
Remote attackers with low privileges can trigger a buffer overflow in the router's web management interface, potentially leading to arbitrary code execution or denial of service on affected TOTOLINK devices.
Affected Products
- TOTOLINK A702R firmware 3.0.0-B20230809.1615
- TOTOLINK A3002R firmware 3.0.0-B20230809.1615
- TOTOLINK A3002RU firmware 3.0.0-B20230809.1615
Discovery Timeline
- 2025-05-17 - CVE-2025-4824 published to NVD
- 2025-05-23 - Last updated in NVD database
Technical Details for CVE-2025-4824
Vulnerability Analysis
The vulnerability resides in the formWsc handler exposed via the /boafrm/formWsc endpoint of the router's embedded web server. When the device receives an HTTP POST request, the handler reads the submit-url parameter and copies its contents into a fixed-size buffer without validating the length of the supplied input. Supplying an oversized value overflows the destination buffer and corrupts adjacent memory.
The Common Weakness Enumeration classifications [CWE-119] and [CWE-120] confirm that the root issue is a classic buffer copy without checking the size of input. Because the vulnerable endpoint is reachable through the device's HTTP management interface, attackers do not need physical access. The exploit has been publicly disclosed, lowering the barrier to weaponization.
The EPSS data places this issue in a high-probability exploitation band relative to other CVEs, reflecting both the public exploit availability and the network reachability of the affected component.
Root Cause
The root cause is missing input length validation in the formWsc request handler before copying the submit-url POST parameter into a stack or heap buffer. Embedded vendors frequently use unsafe C string functions such as strcpy or sprintf in CGI handlers, and the boa-based web server used by TOTOLINK exposes these handlers directly to unauthenticated or low-privileged network clients.
Attack Vector
An attacker sends a crafted HTTP POST request to /boafrm/formWsc on the router's web management interface. The request body contains an oversized submit-url parameter designed to overflow the receiving buffer. Successful exploitation can overwrite return addresses or function pointers, redirecting execution flow within the router's firmware. The attack is network-based and requires only low privileges, making internet-exposed devices particularly at risk.
No verified proof-of-concept code is available in the enriched data. Technical write-ups for the disclosure are referenced in the GitHub Repository Documentation and the VulDB entry #309285.
Detection Methods for CVE-2025-4824
Indicators of Compromise
- HTTP POST requests to /boafrm/formWsc containing unusually long submit-url parameter values, often exceeding several hundred bytes.
- Unexpected reboots, crashes of the boa web server, or loss of management interface availability on TOTOLINK A702R, A3002R, or A3002RU devices.
- Outbound connections from the router to unknown hosts following inbound HTTP POST traffic to the management interface.
Detection Strategies
- Inspect HTTP request logs from the router or upstream network appliances for POST requests targeting /boafrm/formWsc with oversized payloads.
- Deploy network intrusion detection signatures that flag HTTP POST bodies to the formWsc endpoint where the submit-url field exceeds expected lengths.
- Correlate web management traffic with router process crashes or reboot events to identify exploitation attempts.
Monitoring Recommendations
- Restrict and monitor access to the router's HTTP management interface, alerting on any access from outside trusted administrative networks.
- Capture and review syslog or remote logging output from affected TOTOLINK devices for anomalous web server termination messages.
- Track devices matching the vulnerable CPEs in asset inventories to ensure visibility into exposure across the network.
How to Mitigate CVE-2025-4824
Immediate Actions Required
- Remove TOTOLINK A702R, A3002R, and A3002RU devices running firmware 3.0.0-B20230809.1615 from direct internet exposure.
- Disable remote (WAN-side) administration on the router's web interface until a vendor patch is available.
- Restrict LAN-side access to the management interface to a dedicated administrative VLAN or trusted host list.
Patch Information
At the time of publication, the enriched data does not list a vendor advisory or firmware update addressing CVE-2025-4824. Administrators should monitor the TOTOLINK Official Website for firmware releases that supersede 3.0.0-B20230809.1615 and apply them as soon as they are available.
Workarounds
- Block inbound HTTP/HTTPS traffic to the router's management interface from untrusted networks using upstream firewall rules.
- Place affected devices behind a reverse proxy or VPN that enforces authentication before exposing the management plane.
- Replace end-of-life or unsupported TOTOLINK models with hardware that receives active security maintenance.
# Example upstream firewall rule to block external access to the router management interface
# Replace ROUTER_IP with the device address and WAN_IFACE with the upstream interface
iptables -I FORWARD -i WAN_IFACE -p tcp -d ROUTER_IP --dport 80 -j DROP
iptables -I FORWARD -i WAN_IFACE -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.
