The Comcast firmware on Cisco DPC3939 (firmware version dpc3939-P20-18-v303r20421746-170221a-CMCST) and DPC3941T (firmware version DPC3941_2.5s3_PROD_sey) devices allows remote attackers to access the web UI by establishing a session to the wan0 WAN IPv6 address and then entering unspecified hardcoded credentials. This wan0 interface cannot be accessed from the public Internet.
