A buffer overflow vulnerability in the ID processing function in Zyxel ATP series firmware versions 4.32 through 5.36 Patch 1, USG FLEX series firmware versions 4.50 through 5.36 Patch 1, USG FLEX 50(W) firmware versions 4.25 through 5.36 Patch 1, USG20(W)-VPN firmware versions 4.25 through 5.36 Patch 1, VPN series firmware versions 4.30 through 5.36 Patch 1, ZyWALL/USG series firmware versions 4.25 through 4.73 Patch 1, could allow an unauthenticated attacker to cause denial-of-service (DoS) conditions and even a remote code execution on an affected device.

A buffer overflow vulnerability in the notification function in Zyxel ATP series firmware versions 4.60 through 5.36 Patch 1, USG FLEX series firmware versions 4.60 through 5.36 Patch 1, USG FLEX 50(W) firmware versions 4.60 through 5.36 Patch 1, USG20(W)-VPN firmware versions 4.60 through 5.36 Patch 1, VPN series firmware versions 4.60 through 5.36 Patch 1, ZyWALL/USG series firmware versions 4.60 through 4.73 Patch 1, could allow an unauthenticated attacker to cause denial-of-service (DoS) conditions and even a remote code execution on an affected device.

The post-authentication command injection vulnerability in the CLI command of Zyxel ATP series firmware versions 4.32 through 5.35, USG FLEX series firmware versions 4.50 through 5.35, USG FLEX 50(W) firmware versions 4.16 through 5.35, USG20(W)-VPN firmware versions 4.16 through 5.35, and VPN series firmware versions 4.30 through 5.35, which could allow an authenticated attacker to execute some OS commands remotely.

The cross-site scripting (XSS) vulnerability in Zyxel ATP series firmware versions 4.32 through 5.35, USG FLEX series firmware versions 4.50 through 5.35, USG FLEX 50(W) firmware versions 4.16 through 5.35, USG20(W)-VPN firmware versions 4.16 through 5.35, and VPN series firmware versions 4.30 through 5.35, which could allow an authenticated attacker with administrator privileges to store malicious scripts in a vulnerable device. A successful XSS attack could then result in the stored malicious scripts being executed when the user visits the Logs page of the GUI on the device.

A post-authentication information exposure vulnerability in the CGI program of Zyxel ATP series firmware versions 4.32 through 5.35, USG FLEX series firmware versions 4.50 through 5.35, USG FLEX 50(W) firmware versions 4.16 through 5.35, USG20(W)-VPN firmware versions 4.16 through 5.35, VPN series firmware versions 4.30 through 5.35, NWA110AX firmware version 6.50(ABTG.2) and earlier versions, WAC500 firmware version 6.50(ABVS.0) and earlier versions, and WAX510D firmware version 6.50(ABTF.2) and earlier versions, which could allow a remote authenticated attacker to retrieve encrypted information of the administrator on an affected device.

A post-authentication command injection vulnerability in the CLI command of Zyxel ZyWALL/USG series firmware versions 4.20 through 4.72, VPN series firmware versions 4.30 through 5.32, USG FLEX series firmware versions 4.50 through 5.32, and ATP series firmware versions 4.32 through 5.32, which could allow an authenticated attacker with administrator privileges to execute OS commands.

A privilege escalation vulnerability was identified in the CLI command of Zyxel USG FLEX 100(W) firmware versions 4.50 through 5.30, USG FLEX 200 firmware versions 4.50 through 5.30, USG FLEX 500 firmware versions 4.50 through 5.30, USG FLEX 700 firmware versions 4.50 through 5.30, USG FLEX 50(W) firmware versions 4.16 through 5.30, USG20(W)-VPN firmware versions 4.16 through 5.30, ATP series firmware versions 4.32 through 5.30, VPN series firmware versions 4.30 through 5.30, USG/ZyWALL series firmware versions 4.09 through 4.72, which could allow a local attacker to execute some OS commands with root privileges in some directories on a vulnerable device.

A directory traversal vulnerability caused by specific character sequences within an improperly sanitized URL was identified in some CGI programs of Zyxel USG FLEX 100(W) firmware versions 4.50 through 5.30, USG FLEX 200 firmware versions 4.50 through 5.30, USG FLEX 500 firmware versions 4.50 through 5.30, USG FLEX 700 firmware versions 4.50 through 5.30, USG FLEX 50(W) firmware versions 4.16 through 5.30, USG20(W)-VPN firmware versions 4.16 through 5.30, ATP series firmware versions 4.32 through 5.30, VPN series firmware versions 4.30 through 5.30, USG/ZyWALL series firmware versions 4.11 through 4.72, that could allow an authenticated attacker to access some restricted files on a vulnerable device.

An authentication bypasss vulnerability in the web-based management interface of Zyxel USG/Zywall series firmware versions 4.35 through 4.64 and USG Flex, ATP, and VPN series firmware versions 4.35 through 5.01, which could allow a remote attacker to execute arbitrary commands on an affected device.