CVE-2026-10165: Edimax BR-6478AC POST Request formWanTcpipSetup stack-based overflow

Synopsis

A stack-based buffer overflow exists in the Edimax BR-6478AC router (firmware 1.23) in the formWanTcpipSetup function handling POST requests to /goform/formWanTcpipSetup. An authenticated attacker reachable over the network can send a crafted pppUserName argument to overflow the stack, enabling code execution or full compromise of the device's confidentiality, integrity, and availability. No vendor fix has been published; HarborGuard tracks the advisory for patch availability.

HarborGuard Coverage

Exploit Conditions

• Network reachabilityRequired

  The attacker must reach the device's HTTP management interface over the network to deliver the malicious POST request.

• AuthenticationRequired

  A low-privilege account on the router is sufficient to invoke the vulnerable handler.

• Victim interactionNot required

  No user action is needed; the attacker sends the crafted request directly to the device.

• Attack complexityDetail

  Attack complexity is low and a public exploit exists, so the overflow is reliable and condition-free.

Blast Radius

• Executes attacker-controlled code in the context of the router's web management process, typically running with high privilege on the device.
• Reads stored configuration, credentials, and PPP/WAN secrets held by the device.
• Modifies routing, DNS, and firewall configuration to redirect or intercept traffic from connected clients.
• Crashes or bricks the device, disrupting network connectivity for everyone behind it.