CVE-2025-4462 Overview
CVE-2025-4462 is a buffer overflow vulnerability in TOTOLINK N150RT firmware version 3.4.0-B20190525. The flaw resides in the /boafrm/formWsc endpoint, where the localPin argument is processed without proper bounds checking. An authenticated remote attacker can send a crafted request to trigger memory corruption on the router. The exploit details have been disclosed publicly, increasing the likelihood of opportunistic abuse against exposed devices. The vulnerability is classified under [CWE-119] and [CWE-120], covering improper restriction of operations within memory buffers and classic buffer overflow conditions.
Critical Impact
A remote attacker with low privileges can corrupt memory on the TOTOLINK N150RT router via the localPin parameter, leading to potential code execution or denial of service on the device.
Affected Products
- TOTOLINK N150RT router (hardware)
- TOTOLINK N150RT firmware version 3.4.0-B20190525
- Web management interface handler /boafrm/formWsc
Discovery Timeline
- 2025-05-09 - CVE-2025-4462 published to NVD
- 2025-05-23 - Last updated in NVD database
Technical Details for CVE-2025-4462
Vulnerability Analysis
The vulnerability resides in the HTTP handler /boafrm/formWsc implemented in the boa web server running on the TOTOLINK N150RT. This endpoint processes Wi-Fi Protected Setup (WPS) configuration submissions. The localPin parameter, expected to contain an 8-digit WPS PIN, is copied into a fixed-size stack buffer without validating its length. Supplying an oversized value overflows adjacent stack memory, including saved return addresses.
The device runs on a MIPS-based SoC with limited exploit mitigations. Stack canaries, ASLR, and non-executable stacks are typically absent or weak on this class of consumer router. Successful exploitation can hijack control flow and execute attacker-supplied instructions as the web server process, which runs with elevated privileges on the device.
Root Cause
The root cause is missing input length validation before a memory copy operation on the localPin parameter inside the formWsc handler. The function trusts the attacker-controlled length, satisfying the definition of [CWE-120] buffer copy without checking input size.
Attack Vector
The attack vector is network-based against the router's web administration interface. The CVSS metrics indicate low attack complexity and require low privileges, meaning the attacker needs valid credentials or session access to the management UI. No user interaction is required. Devices exposing the management interface to the WAN or to untrusted LAN segments are at highest risk.
// Vulnerability description - no verified exploit code published inline
// See the referenced PoC repository for technical reproduction details:
// https://github.com/fizz-is-on-the-way/Iot_vuls/tree/main/N150RT/BufferOverflow_formWsc_2
A proof-of-concept is published at the GitHub Buffer Overflow PoC repository.
Detection Methods for CVE-2025-4462
Indicators of Compromise
- HTTP POST requests to /boafrm/formWsc containing an abnormally long localPin parameter value exceeding the expected 8-character WPS PIN length.
- Unexpected reboots, crashes, or watchdog resets of the TOTOLINK N150RT during or after web administration sessions.
- Outbound connections from the router to unfamiliar hosts following web UI access from non-administrative source IPs.
Detection Strategies
- Inspect HTTP request payloads at the network edge for requests targeting /boafrm/formWsc with localPin values longer than the expected WPS PIN format.
- Correlate router syslog entries showing process crashes in the boa web server with prior authenticated sessions to flag exploitation attempts.
- Baseline normal management traffic patterns and alert on bursts of malformed POST bodies targeting the router's administrative endpoints.
Monitoring Recommendations
- Forward router logs to a centralized log platform and create alerts on boa segfaults, restarts, or authentication anomalies.
- Monitor management interfaces of consumer-grade routers for inbound connections from outside expected administrator subnets.
- Track firmware versions across deployed TOTOLINK devices to identify hosts still running 3.4.0-B20190525.
How to Mitigate CVE-2025-4462
Immediate Actions Required
- Disable WAN-side access to the router's web administration interface and restrict LAN-side access to a dedicated management VLAN.
- Change default and weak administrative credentials to limit who can reach the authenticated formWsc handler.
- Disable WPS on the router if not strictly required, reducing exposure of the affected code path.
- Isolate the N150RT from sensitive network segments until a vendor patch is applied.
Patch Information
No fixed firmware version is listed in the NVD entry or referenced advisories at the time of publication. Administrators should monitor the TOTOLINK Official Website and the VulDB #308081 entry for updated firmware. Where no patch is available, consider replacing the device with a supported model.
Workarounds
- Block external access to TCP port 80 and 443 on the router's WAN interface using upstream firewall rules.
- Apply ACLs that permit administrative HTTP/HTTPS traffic only from trusted internal IP addresses.
- Turn off WPS functionality in the router configuration to eliminate the formWsc code path from normal use.
- Replace end-of-life TOTOLINK N150RT hardware with a vendor-supported router that receives security updates.
# Example upstream firewall rule to restrict access to router management
# Replace 192.0.2.10 with the trusted administrator workstation IP
# and 198.51.100.1 with the router's LAN IP
iptables -A FORWARD -s 192.0.2.10 -d 198.51.100.1 -p tcp --dport 80 -j ACCEPT
iptables -A FORWARD -d 198.51.100.1 -p tcp --dport 80 -j DROP
iptables -A FORWARD -d 198.51.100.1 -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.
