CVE-2025-57573 Overview
CVE-2025-57573 is a buffer overflow vulnerability [CWE-120] affecting the Tenda F3 wireless router. The flaw resides in the goform/setWifi endpoint, where the wifiTimeClose parameter is copied into a fixed-size buffer without proper bounds checking. Attackers reachable over the network can send a crafted HTTP request to trigger memory corruption on the device. The vulnerability affects Tenda F3 firmware version V12.01.01.48_multi and later releases within that branch.
Critical Impact
Successful exploitation can crash the router or potentially allow arbitrary code execution in the context of the web management daemon, disrupting network availability for connected clients.
Affected Products
- Tenda F3 router hardware
- Tenda F3 firmware version 12.01.01.48
- Later firmware builds in the V12.01.01.48_multi branch
Discovery Timeline
- 2025-09-10 - CVE-2025-57573 published to NVD
- 2026-07-05 - Last updated in NVD database
Technical Details for CVE-2025-57573
Vulnerability Analysis
The vulnerability is a classic stack-based buffer overflow in the router's HTTP configuration handler. The setWifi handler in /goform/setWifi reads the wifiTimeClose query parameter from an incoming request and passes it to an internal string copy routine without validating its length. Because the destination buffer has a fixed size on the stack, an overly long value overwrites adjacent memory including saved registers and return addresses.
The web service on Tenda SOHO devices typically runs with root privileges, so memory corruption in the request handler translates directly into full device compromise if code execution is achieved. The requirement for network reachability but no authentication makes the LAN-side attack surface broad for anyone already on the wireless network.
Root Cause
The root cause is missing input length validation on the wifiTimeClose parameter inside the HTTP form handler binary. The firmware relies on unbounded string operations such as strcpy or sprintf when composing configuration values, a pattern common across Tenda's goform handlers.
Attack Vector
An attacker sends an HTTP POST or GET request to /goform/setWifi on the router's management interface with an oversized wifiTimeClose value. The router parses the request, copies the parameter into a stack buffer, and overflows adjacent memory. Depending on payload construction, the outcome ranges from a service crash and reboot to hijacked control flow. Additional technical detail is available in the public write-up on GitHub.
Detection Methods for CVE-2025-57573
Indicators of Compromise
- HTTP requests to /goform/setWifi containing unusually long wifiTimeClose values (hundreds or thousands of bytes)
- Unexpected reboots or crashes of the router's httpd process visible in device logs
- Loss of management interface availability following a targeted HTTP request from a LAN client
Detection Strategies
- Inspect HTTP traffic to the router administration interface for oversized query string or form parameters targeting goform endpoints
- Alert on repeated malformed requests to /goform/setWifi originating from a single LAN host
- Correlate router availability drops with preceding HTTP traffic patterns to identify exploitation attempts
Monitoring Recommendations
- Forward router syslog to a central collector and monitor for httpd restarts or watchdog resets
- Restrict administrative access to the router to a management VLAN and log all connections to TCP/80 and TCP/443 on the device
- Baseline normal parameter lengths for goform requests and flag statistical outliers
How to Mitigate CVE-2025-57573
Immediate Actions Required
- Disable remote (WAN-side) administration on the Tenda F3 if it is enabled
- Segment the router's management interface onto a trusted VLAN and block access from guest or IoT networks
- Rotate the router administrator password and disable WPS to reduce the pool of hosts that can reach the LAN interface
Patch Information
No vendor patch or security advisory from Tenda is referenced in the NVD entry at the time of publication. Owners of affected devices should monitor Tenda's support pages for firmware updates and consider replacing end-of-life hardware if no fix is released. Additional technical context is documented in the public CVE write-up.
Workarounds
- Place the router behind a network firewall that filters unsolicited HTTP traffic to the management interface
- Restrict which LAN clients can reach the router's administrative IP using switch-level ACLs where available
- Replace the Tenda F3 with a currently supported device if operating in a sensitive environment
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
