The HTTPD binary in multiple ZTE routers has a local file inclusion vulnerability in session_init function. The session -LUA- files are stored in the directory /var/lua_session, the function iterates on all files in this directory and executes them using the function dofile without any validation if it is a valid session file or not. An attacker who is able to write a malicious file in the sessions directory can get RCE as root.
The product imports, requires, or includes executable functionality (such as a library) from a source that is outside of the intended control sphere.