Tenda W12 Administrative shadow hard-coded credentials

A security vulnerability has been detected in Tenda W12 up to 3.0.0.6(3948). Affected is an unknown function of the file /etc_ro/shadow of the component Administrative Interface. The manipulation leads to hard-coded credentials. An attack has to be approached locally. The complexity of an attack is rather high. The exploitability is told to be difficult. The exploit has been disclosed publicly and may be used.