The AC5300 Ultra WiFi router looks "Ultra" and new.
Looks interesting right? lots of new specs and capabilities. Now let's check out security researcher at /dev/TTYS0
So, while Dlink was busy with their marketing campaign and trying to sell more routers with flashy products and images (after a certain engineering effort), the security researcher looks into the machine and finds the same bad firmware with respect to the exploits and how to hack routers like from zcutlip/eploit-poc which is a buffer overflow vulnerability.
It is obvious that Dlink is not spending any or very little money on security research.
It looks like the HNAP protocol on several devices are vulnerable to getting hacked by astute criminal hackers.
The system will get owned very quickly, a telnet command line prompt will be opened by the criminal hacker.
Although their products look interesting, they are not paying enough attention to securing their devices. And not spending money fixing their firmware.
We all have to pay more attention to Security, and design products properly.
People that buy products need to understand which companies pay attention to security.
Cybersecurity is a reactive environment.
New exploits come out, the manufacturers have to have the resources to keep up on these new exploits, it seems D-Link is not keeping up.