Improper access control

An issue was discovered on Zyxel GS1900 devices with firmware before 2.50AAHH.0C0. Through an undocumented sequence of keypresses, undocumented functionality is triggered. A diagnostics shell is triggered via CTRL-ALT-t, which prompts for the password returned by fdssyspassDebugPasswdret. The...

CVE-2019-15801

An issue was discovered on Zyxel GS1900 devices with firmware before 2.50AAHH.0C0. The firmware image contains encrypted passwords that are used to authenticate users wishing to access a diagnostics or password-recovery menu. Using the hardcoded cryptographic key found elsewhere in the firmware,...