CVE-2026-10181: TRENDnet TEW-432BRP formSysCmd stack-based overflow

Synopsis

A stack-based buffer overflow exists in the formSysCmd handler of the TRENDnet TEW-432BRP wireless router (firmware 3.10B20). The flaw is reachable over the network by an authenticated attacker who manipulates the submit-url argument in an HTTP request to /goform/formSysCmd, overflowing a fixed-size stack buffer. Successful exploitation gives the attacker full control over the device, enabling remote code execution, data disclosure, and service disruption. No patch exists and none is expected; TRENDnet has declared the device end-of-life since 2009 and will not issue a fix. HarborGuard tracks this advisory and will make a patched rebuild available if an upstream fix is ever published.

HarborGuard Coverage

Exploit Conditions

• Network reachabilityRequired

  The vulnerable endpoint /goform/formSysCmd is exposed over the network, so the attacker must be able to reach the device's HTTP service from the internet or an internal network segment.

• AuthenticationRequired

  The attack requires a valid low-privilege account on the router's web interface; unauthenticated access alone is not sufficient to reach the formSysCmd handler.

• Victim interactionNot required

  No user interaction is needed; the attacker sends a crafted HTTP request directly to the device without relying on any victim action.

• Attack complexityDetail

  Attack complexity is low, meaning the overflow is reliably triggered by a single malformed request with no race conditions or special environmental preconditions required.

Blast Radius

• The attacker gains the ability to execute arbitrary code in the context of the router firmware, effectively taking full control of the device.
• All traffic routed through the device becomes readable and modifiable by the attacker, exposing credentials, session tokens, and any unencrypted data in transit.
• The attacker can modify persistent router configuration, including DNS settings and firewall rules, affecting every client on the network.
• The router process can be crashed or made unresponsive, disrupting network connectivity for all connected clients.