wan.htm page on Zyxel NBG-418N v2 with firmware version V1.00(AARP.9)C0 can be accessed directly without authentication, which can lead to disclosure of information about the WAN, and can also be leveraged by an attacker to modify data fields of the page.

A reflective Cross-site scripting (XSS) vulnerability in the free_time_failed.cgi CGI program in selected Zyxel ZyWall, USG, and UAG devices allows remote attackers to inject arbitrary web script or HTML via the err_msg parameter.

Missing Access Control in the "Free Time" component of several Zyxel UAG, USG, and ZyWall devices allows a remote attacker to generate guest accounts by directly accessing the account generator. This can lead to unauthorised network access or Denial of Service.

The rpWLANRedirect.asp ASP page is accessible without authentication on ZyXEL P-660HN-T1 V2 (2.00(AAKK.3)) devices. After accessing the page, the admin user's password can be obtained by viewing the HTML source code, and the interface of the modem can be accessed as admin.

The ZyXEL P660HN-T1A v1 TCLinux Fw $7.3.15.0 v001 / 3.40(ULM.0)b31 router distributed by TrueOnline has a command injection vulnerability in the Remote System Log forwarding function, which is accessible by an unauthenticated user. The vulnerability is in the ViewLog.asp page and can be exploited through the remote_host parameter.

The ZyXEL P660HN-T1A v2 TCLinux Fw #7.3.37.6 router distributed by TrueOnline has three user accounts with default passwords, including two hardcoded service accounts: one with the username true and password true, and another with the username supervisor and password zyad1234. These accounts can be used to login to the web interface, exploit authenticated command injections, and change router settings for malicious purposes.

The ZyXEL P660HN-T1A v1 TCLinux Fw $7.3.15.0 v001 / 3.40(ULM.0)b31 router distributed by TrueOnline has two user accounts with default passwords, including a hardcoded service account with the username true and password true. These accounts can be used to login to the web interface, exploit authenticated command injections and change router settings for malicious purposes.

The ZyXEL P660HN-T1A v2 TCLinux Fw #7.3.37.6 router distributed by TrueOnline has a command injection vulnerability in the Remote System Log forwarding function, which is only accessible by an authenticated user. The vulnerability is in the logSet.asp page and can be exploited through the ServerIP parameter. Authentication can be achieved by exploiting CVE-2017-18371.

The Billion 5200W-T TCLinux Fw $7.3.8.0 v008 130603 router distributed by TrueOnline has a command injection vulnerability in the Time Setting function, which is only accessible by an authenticated user. The vulnerability is in the tools_time.asp page and can be exploited through the uiViewSNTPServer parameter. Authentication can be achieved by exploiting CVE-2017-18373.

On Zyxel ATP200, ATP500, ATP800, USG20-VPN, USG20W-VPN, USG40, USG40W, USG60, USG60W, USG110, USG210, USG310, USG1100, USG1900, USG2200-VPN, ZyWALL 110, ZyWALL 310, ZyWALL 1100 devices, the security firewall login page is vulnerable to Reflected XSS via the unsanitized 'mp_idx' parameter.