The Huawei E355 adapter with firmware 21.157.37.01.910 does not require authentication for API pages, which allows remote attackers to change passwords and settings, or obtain sensitive information, via a direct request to (1) api/wlan/security-settings, (2) api/device/information, (3) api/wlan/basic-settings, (4) api/wlan/mac-filter, (5) api/monitoring/status, or (6) api/dhcp/settings.