A critical stack-based buffer overflow in Tenda AC8 allows unauthenticated remote attackers to execute arbitrary code via the HTTP interface.

The vulnerability exists in the doSystemCmd function of the /goform/SysToolChangePwd file. An unauthenticated remote attacker can trigger a stack-based buffer overflow by manipulating the local_2c argument.

The CVSS score of 9.8 underscores the extreme risk posed by this vulnerability. Remote code execution on networking hardware like the Tenda AC8 can allow attackers to intercept traffic, redirect users, or gain persistence within the local network, leading to widespread data compromise.

Immediate Action: Update the Tenda AC8 firmware to the latest available version provided by the manufacturer.

Proactive Monitoring: Monitor network traffic for unusual HTTP requests targeting the /goform/SysToolChangePwd endpoint.

Compensating Controls: Restrict access to the router's management interface to trusted internal IP addresses only.

Public Exploit Available: Yes

Due to the availability of public exploits and the critical nature of the flaw, immediate firmware updates are required. Organizations should ensure that management interfaces are not exposed to the public internet and apply the patch as soon as it is released by Tenda.