Zyxel DSL and Ethernet CPE Command Injection Vulnerability in DHCP Configuration

A post-authentication command injection vulnerability has been identified in the "DomainName" parameter of the DHCP configuration file for Zyxel DX3301-T0 and EX3301-T0 models, running firmware versions through 5.50(ABVY.7.1)C0. This vulnerability allows an authenticated attacker with administrator privileges to execute operating system commands on the affected device. WAN access is disabled by default on these devices, so exploitation would require knowledge of user-configured passwords.

Impact

Exploitation of this vulnerability could lead to unauthorized command execution on the affected device's operating system.

Remediation

Users are advised to update to version 5.50(ABVY.7.2)C0. For devices purchased through an ISP, contact the ISP's support team. For other users, reach out to the local Zyxel support team or visit Zyxel's Community for assistance.