CVE-2026-10163: Edimax BR-6478AC POST Request formUSBAccount buffer overflow

Synopsis

A buffer overflow in the Edimax BR-6478AC router affects the formUSBAccount handler reachable at /goform/formUSBAccount. The bug is triggered by oversized UserName or Password values in a POST request, reachable over the network with any low-privilege account on the device's management interface, and successful exploitation lets an attacker compromise confidentiality, integrity, and availability on the device. No upstream fix has been published, so HarborGuard tracks the advisory for patch availability.

HarborGuard Coverage

Exploit Conditions

• Network reachabilityRequired

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

• AuthenticationRequired

  PR:L indicates any low-privilege account on the device is sufficient to invoke the vulnerable handler.

• Victim interactionNot required

  UI:N means no administrator or user action is needed; the attacker drives the exploit directly.

• Attack complexityDetail

  AC:L indicates the exploit is reliable and free of race conditions or environmental prerequisites, and a public proof of concept has been disclosed.

Blast Radius

• Executes attacker-controlled code or corrupts memory in the router's web management process, with full read access to stored credentials and configuration.
• Modifies device configuration, including USB account settings, routing, and firewall rules persisted on the device.
• Crashes or hangs the management service, disrupting administration and potentially network connectivity for clients behind the router.