An issue discovered on D-Link DIR-615 devices with firmware version 20.05 and 20.07. wan.htm can be accessed directly without authentication, which can lead to disclosure of information about the WAN, and can also be leveraged by an attacker to modify the data fields of the page.
https://www.ftc.gov/system/files/documents/cases/dlink_proposed_order_and_judgment_7-2-19.pdf
https://www.dlink.com/en/security-bulletin
https://us.dlink.com/en/security-advisory
https://github.com/d0x0/D-Link-DIR-615/blob/master/CVE-2019-17353