CVE-2026-3168 Overview
CVE-2026-3168 is a buffer overflow vulnerability in Tenda F453 routers running firmware version 1.0.0.3. The flaw resides in the fromNatStaticSetting function within the /goform/NatStaticSetting endpoint of the httpd component. Attackers can manipulate the page argument to trigger memory corruption. The vulnerability is remotely exploitable over the network and a public exploit has been disclosed, increasing the likelihood of opportunistic attacks against exposed devices. The weakness is classified under [CWE-119] (Improper Restriction of Operations within the Bounds of a Memory Buffer).
Critical Impact
Remote attackers with low-privileged access can corrupt memory in the router's HTTP daemon, potentially achieving arbitrary code execution and full device compromise.
Affected Products
- Tenda F453 router (hardware)
- Tenda F453 Firmware version 1.0.0.3
- Deployments exposing the web management interface (httpd) to untrusted networks
Discovery Timeline
- 2026-02-25 - CVE-2026-3168 published to NVD
- 2026-02-25 - Last updated in NVD database
Technical Details for CVE-2026-3168
Vulnerability Analysis
The vulnerability exists in the fromNatStaticSetting handler exposed through the /goform/NatStaticSetting URI on the Tenda F453 httpd service. The handler processes the page query parameter without validating its length before copying it into a fixed-size stack or heap buffer. Supplying an oversized page value overflows the destination buffer, corrupting adjacent memory structures including saved return addresses and function pointers.
The httpd binary on Tenda small office and home office (SOHO) routers typically runs with elevated privileges. Successful exploitation can therefore lead to remote code execution within the router's operating environment, enabling persistent compromise, traffic interception, and lateral movement into the LAN.
Root Cause
The root cause is a missing bounds check on attacker-controlled input. The fromNatStaticSetting function reads the page parameter from the HTTP request and writes it into a buffer of fixed length using an unsafe copy routine such as strcpy or sprintf. Without length validation, request data exceeding the buffer size overwrites adjacent memory.
Attack Vector
An authenticated attacker on the network sends a crafted HTTP request to the /goform/NatStaticSetting endpoint with an oversized page parameter. The request requires low privileges and no user interaction. Because the management interface is sometimes exposed to the WAN side, internet-reachable devices face elevated risk.
Technical details of the request structure and parameter handling are documented in the GitHub Vulnerability Documentation and VulDB entry #347675.
Detection Methods for CVE-2026-3168
Indicators of Compromise
- Unusual or repeated HTTP POST/GET requests to /goform/NatStaticSetting containing abnormally long page parameter values.
- Unexpected restarts or crashes of the httpd process on the Tenda F453.
- Outbound connections from the router to unfamiliar hosts following exploitation attempts.
- New or modified NAT/firewall rules on the device that were not made by administrators.
Detection Strategies
- Inspect web access logs and network flow data for requests targeting /goform/NatStaticSetting with payloads exceeding expected parameter lengths.
- Deploy network intrusion detection signatures that flag oversized query string values directed at Tenda httpd URIs.
- Monitor for anomalous traffic patterns or sudden configuration changes on edge networking equipment.
Monitoring Recommendations
- Centralize router and gateway logs into a SIEM for correlation with broader network telemetry.
- Track device firmware versions through asset inventory and alert when vulnerable versions remain in production.
- Establish baselines for management interface traffic so deviations involving the /goform/ paths trigger investigation.
How to Mitigate CVE-2026-3168
Immediate Actions Required
- Restrict access to the Tenda F453 web management interface to trusted management VLANs only.
- Disable WAN-side administration if it is enabled, ensuring the device cannot be managed from the internet.
- Rotate administrative credentials, since the vulnerability requires low-privilege authenticated access.
- Audit NAT and port-forwarding rules for unauthorized modifications.
Patch Information
No official patch from Tenda has been published in the referenced advisories at the time of NVD publication. Consult the Tenda Official Site for firmware updates and security bulletins. Where no vendor fix is available, organizations should plan migration to a supported router platform.
Workarounds
- Place the router behind a network segmentation boundary that blocks untrusted hosts from reaching the management port.
- Apply ACLs on upstream equipment to deny inbound traffic to the router's HTTP service from the WAN.
- Replace end-of-life or unpatched Tenda F453 devices with vendor-supported hardware that receives security updates.
# Example iptables rule to restrict access to the router's web UI to a management subnet
iptables -A INPUT -p tcp --dport 80 -s 192.0.2.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
