CVE-2025-4829 Overview
CVE-2025-4829 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 sub_40BE30 function within /boafrm/formStats, a component of the HTTP POST Request Handler. An attacker can manipulate the submit-url argument to trigger memory corruption. The exploit has been publicly disclosed, increasing the risk of opportunistic attacks against exposed devices. The vulnerability is categorized under [CWE-119] and [CWE-120], covering improper restriction of operations within memory buffer bounds and classic buffer copy without size checking.
Critical Impact
Remote attackers with low-level privileges can corrupt router memory over the network, 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-2025-4829 published to NVD
- 2025-05-23 - Last updated in NVD database
Technical Details for CVE-2025-4829
Vulnerability Analysis
The vulnerability exists in the sub_40BE30 function inside the /boafrm/formStats endpoint of the device's embedded HTTP server. The function processes the submit-url parameter from HTTP POST requests without enforcing length validation. An attacker who reaches the endpoint can submit an oversized value to overflow an internal buffer. The overflow corrupts adjacent memory regions on the router's processor stack or heap, depending on allocation context. Successful exploitation can yield arbitrary code execution in the context of the router's web service, full compromise of the device, or persistent denial of service. Because TOTOLINK routers run with high privileges on a constrained embedded Linux platform, code execution typically grants root-level control over network traffic.
Root Cause
The root cause is missing bounds checking on user-controlled input before copying it into a fixed-size buffer. The formStats handler trusts the submit-url parameter and passes it to sub_40BE30 without validating length or content. This pattern matches [CWE-120], a classic buffer copy without checking input size.
Attack Vector
The attack vector is network-based and requires only low privileges. An attacker sends a crafted HTTP POST request to /boafrm/formStats with an oversized submit-url parameter. No user interaction is required. If the router's management interface is reachable from the WAN or compromised LAN, the attack can be conducted remotely. Public disclosure on the GitHub PoC Repository lowers the barrier to weaponization. The EPSS score of 0.98% places this vulnerability in the upper percentile of likely-exploited issues tracked by FIRST.
No verified exploit code is reproduced here. Refer to the VulDB CTI Report #309295 for additional technical context.
Detection Methods for CVE-2025-4829
Indicators of Compromise
- HTTP POST requests to /boafrm/formStats containing abnormally long submit-url parameter values
- Unexpected reboots or crashes of the router's boa web server process
- New or modified firewall rules, DNS settings, or administrative accounts on affected TOTOLINK devices
- Outbound connections from the router to unknown command-and-control infrastructure
Detection Strategies
- Inspect web access logs on the router (when available) for requests targeting /boafrm/formStats with payload sizes exceeding expected URL lengths
- Deploy network-based intrusion detection signatures that flag POST requests to formStats containing oversized submit-url fields
- Monitor for behavioral anomalies such as routers initiating scans, brute-force traffic, or DDoS amplification
Monitoring Recommendations
- Forward router syslog and network flow data to a centralized SIEM for correlation
- Track baseline HTTP request sizes to the device management interface and alert on outliers
- Audit exposure of router management ports on internet-facing interfaces using external attack surface management tools
How to Mitigate CVE-2025-4829
Immediate Actions Required
- Restrict access to the router management interface to trusted internal networks only and disable WAN-side administration
- Place affected TOTOLINK devices behind a network segmentation boundary that filters traffic to /boafrm/formStats
- Rotate administrative credentials on affected devices to reduce risk of authenticated exploitation
- Inventory all TOTOLINK A702R, A3002R, and A3002RU units running firmware 3.0.0-B20230809.1615
Patch Information
No vendor patch has been listed in the NVD or vendor advisory references at the time of publication. Consult the Totolink Official Website for firmware updates and subscribe to vendor notifications. If no fixed firmware is available, treat affected devices as end-of-support and plan replacement with hardware that receives security updates.
Workarounds
- Disable remote HTTP management on the WAN interface of affected routers
- Implement an upstream firewall or reverse proxy that drops POST requests to /boafrm/formStats with submit-url values exceeding a strict length threshold
- Segment vulnerable routers into isolated VLANs with restricted access to administrative endpoints
- Replace end-of-life TOTOLINK firmware with supported alternatives where feasible
# Example upstream firewall rule (iptables) limiting access to router management
iptables -A FORWARD -p tcp -d <router_ip> --dport 80 -s <trusted_mgmt_subnet> -j ACCEPT
iptables -A FORWARD -p tcp -d <router_ip> --dport 80 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
