CVE-2025-3328: Tenda AC1206 Buffer Overflow Vulnerability

CVE-2025-3328 Overview

CVE-2025-3328 is a buffer overflow vulnerability in the Tenda AC1206 wireless router running firmware version 15.03.06.23. The flaw resides in the form_fast_setting_wifi_set function handling requests to /goform/fast_setting_wifi_set. Attackers manipulate the ssid and timeZone arguments to trigger memory corruption [CWE-119, CWE-787]. The vulnerability is remotely exploitable and public exploit details have been disclosed. Other parameters processed by the same handler may also be affected.

Critical Impact
Remote attackers with low privileges can corrupt router memory and potentially achieve arbitrary code execution on the device, compromising the network perimeter.

Affected Products

Tenda AC1206 router (hardware)
Tenda AC1206 firmware version 15.03.06.23
Devices exposing the /goform/fast_setting_wifi_set endpoint

Discovery Timeline

2025-04-07 - CVE-2025-3328 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-3328

Vulnerability Analysis

The vulnerability lives in the form_fast_setting_wifi_set function exposed through the router web interface at /goform/fast_setting_wifi_set. This handler implements the fast Wi-Fi setup workflow and accepts user-supplied parameters including ssid and timeZone. The function copies these parameters into fixed-size stack or heap buffers without validating their length.

The weakness maps to CWE-119 (improper restriction of operations within memory bounds) and CWE-787 (out-of-bounds write). Submitting an oversized value for ssid or timeZone overruns the destination buffer and overwrites adjacent memory. The EPSS score of 5.021% places this issue in the 91st percentile for likelihood of exploitation activity.

Root Cause

The handler uses unsafe string copy operations on attacker-controlled HTTP POST parameters. Tenda's firmware does not enforce a maximum length on ssid or timeZone before writing to the destination buffer. The result is a classic stack or heap overflow on a MIPS-based embedded device with limited exploit mitigations.

Attack Vector

The attack vector is network-based and requires only low privileges, matching the credentials present on many deployed Tenda devices using default or weak passwords. An attacker sends a crafted HTTP POST request to /goform/fast_setting_wifi_set with an oversized ssid or timeZone value. Successful exploitation corrupts memory and can lead to denial of service or arbitrary code execution in the context of the web management process, which typically runs with root privileges on Tenda firmware.

For technical request structure and parameter analysis, see the GitHub configuration documentation for form_fast_setting_wifi_set and the timeZone parameter analysis.

Detection Methods for CVE-2025-3328

Indicators of Compromise

HTTP POST requests to /goform/fast_setting_wifi_set containing unusually long ssid or timeZone values exceeding typical lengths (32 characters for SSID, short strings for timezone identifiers).
Repeated requests to the fast setup endpoint from external or unexpected source addresses.
Unexpected router reboots, dropped management sessions, or web UI crashes following inbound traffic to the goform handler.
Outbound connections from the router to attacker-controlled infrastructure after exploitation.

Detection Strategies

Inspect HTTP traffic to Tenda router management interfaces for POST bodies containing oversized parameter values targeting /goform/ endpoints.
Deploy network IDS signatures that flag requests to fast_setting_wifi_set with parameter lengths beyond protocol-reasonable bounds.
Correlate router syslog or remote logging output with web request logs to identify crash-restart cycles tied to specific source addresses.

Monitoring Recommendations

Restrict and monitor exposure of router web management interfaces, ensuring they are not reachable from the WAN.
Log all administrative access to embedded network devices and forward those logs to a central analysis platform.
Alert on Tenda AC1206 devices reporting firmware 15.03.06.23 in asset inventories and track patch status.

How to Mitigate CVE-2025-3328

Immediate Actions Required

Disable remote (WAN-side) administration on all Tenda AC1206 devices and restrict management access to trusted internal hosts only.
Change default credentials on the router web interface to reduce the chance of low-privilege exploitation.
Segment Tenda AC1206 devices from sensitive network zones until a vendor patch is verified and applied.
Inventory affected devices running firmware 15.03.06.23 and prioritize replacement or isolation.

Patch Information

At the time of publication, no fixed firmware version has been listed in the NVD entry or referenced vendor materials. Monitor the Tenda official website for AC1206 firmware updates addressing the form_fast_setting_wifi_set handler. Additional tracking is available via VulDB entry 303540.

Workarounds

Block external access to TCP ports used by the router web management interface at the upstream firewall.
Place an inline web application firewall or reverse proxy in front of the management UI to reject POST requests with oversized ssid or timeZone parameters.
Disable the fast Wi-Fi setup wizard after initial configuration where the firmware permits.
Replace end-of-support consumer routers with vendor-supported hardware that receives ongoing security updates.

bash

# Example upstream firewall rule to block WAN access to router management
# Adjust interface and router IP for your environment
iptables -A FORWARD -i wan0 -d 192.168.0.1 -p tcp --dport 80 -j DROP
iptables -A FORWARD -i wan0 -d 192.168.0.1 -p tcp --dport 443 -j DROP

# Block inbound POSTs to the vulnerable goform handler at a reverse proxy (nginx)
# location /goform/fast_setting_wifi_set {
#     if ($request_method = POST) { return 403; }
# }