The certificate and private key used for providing transport layer security for connections to the web interface (TCP port 443) is hard-coded in the firmware and are shipped with the update files. An attacker can use the private key to perform man-in-the-middle attacks against users of the admin interface. The files are located in /etc/ssl (e.g. salia.local.crt, salia.local.key and salia.local.pem). There is no option to upload/configure custom TLS certificates.
The use of a hard-coded cryptographic key significantly increases the possibility that encrypted data may be recovered.