CVE-2025-57570 Overview
CVE-2025-57570 is a buffer overflow vulnerability affecting Tenda F3 routers running firmware version V12.01.01.48_multi and later. The flaw resides in the goform/setQoS endpoint, where the QosList parameter is processed without proper bounds checking. Attackers can send crafted HTTP requests to trigger the overflow, potentially corrupting memory on the device. The vulnerability is classified under [CWE-120] (Buffer Copy without Checking Size of Input). Exploitation occurs over the network without authentication, though attack complexity is high.
Critical Impact
Successful exploitation may lead to memory corruption on affected Tenda F3 routers, resulting in denial of service or potential code execution against the router's management interface.
Affected Products
- Tenda F3 router (hardware)
- Tenda F3 firmware version 12.01.01.48
- Tenda F3 firmware versions released after V12.01.01.48_multi
Discovery Timeline
- 2025-09-10 - CVE-2025-57570 published to NVD
- 2026-07-05 - Last updated in NVD database
Technical Details for CVE-2025-57570
Vulnerability Analysis
The vulnerability exists in the HTTP request handler for /goform/setQoS on the Tenda F3 router web management interface. This endpoint is responsible for configuring Quality of Service (QoS) rules on the device. When the handler processes the QosList parameter supplied by the client, it copies the value into a fixed-size stack buffer without validating the input length.
An attacker who can reach the router's HTTP management interface can send a request containing an oversized QosList value. The excess data overwrites adjacent stack memory, corrupting saved registers and return addresses. This creates conditions for denial of service or potential arbitrary code execution within the router's firmware context.
The exploit requires network reachability to the router's management port. While no authentication is required, the attack complexity is high, which typically reflects timing constraints or non-deterministic conditions in achieving reliable exploitation. The EPSS score indicates low probability of exploitation activity in the near term.
Root Cause
The root cause is missing input length validation on the QosList parameter within the goform/setQoS handler. The firmware performs an unbounded copy into a stack-allocated buffer, a common pattern in embedded MIPS/ARM router binaries where strcpy or sprintf operations are used without size limits.
Attack Vector
An attacker sends a specially crafted HTTP POST request to /goform/setQoS on the router with an overly long QosList parameter value. The request must originate from a network position that can reach the router's HTTP interface, typically the LAN or, if remote management is enabled, the WAN. Refer to the GitHub CVE-2025-57570 Documentation for technical reproduction details.
Detection Methods for CVE-2025-57570
Indicators of Compromise
- Unexpected reboots or crashes of the Tenda F3 router coinciding with HTTP traffic to /goform/setQoS
- HTTP POST requests to /goform/setQoS containing abnormally long QosList parameter values
- Router management interface becoming unresponsive after receiving crafted QoS configuration requests
Detection Strategies
- Inspect HTTP traffic destined for the router's management interface for oversized parameter values in goform endpoints
- Deploy network intrusion detection signatures that flag POST requests to /goform/setQoS exceeding expected parameter length thresholds
- Correlate router availability events with recent HTTP configuration requests
Monitoring Recommendations
- Monitor router syslog output for watchdog resets, segmentation faults, or httpd process crashes
- Track access to the router's HTTP management port from unexpected internal hosts
- Alert on WAN-side connection attempts to router management ports if remote administration is disabled
How to Mitigate CVE-2025-57570
Immediate Actions Required
- Disable remote (WAN-side) HTTP management on the Tenda F3 router to reduce exposure to external attackers
- Restrict LAN access to the router management interface to trusted administrative hosts only
- Segment IoT and network infrastructure devices onto a management VLAN with strict ACLs
Patch Information
No vendor patch is currently referenced in the CVE record. Users should monitor the Tenda support portal for firmware updates addressing this issue. If a fixed firmware version becomes available, apply it promptly through the router's administrative interface.
Workarounds
- Place the Tenda F3 router behind a firewall that blocks untrusted access to TCP port 80/443 on the device
- Change default administrative credentials and disable UPnP to limit attacker pivot options
- Consider replacing the affected device if no vendor patch is released and the router is deployed in a security-sensitive environment
# Example: block external access to router management interface using iptables on an upstream gateway
iptables -A FORWARD -p tcp -d <router_ip> --dport 80 -m iprange ! --src-range 192.168.1.0-192.168.1.255 -j DROP
iptables -A FORWARD -p tcp -d <router_ip> --dport 443 -m iprange ! --src-range 192.168.1.0-192.168.1.255 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
