A directory traversal vulnerability in the file browser component on the Zyxel NAS 326 version 5.21 and below allows a lower privileged user to change the location of any other user's files.

Shell Metacharacter Injection in the package installer on Zyxel NAS 326 version 5.21 and below allows an authenticated attacker to execute arbitrary code via multiple different requests.

A plaintext password vulnerability in the Zyxel NAS 326 through 5.21 allows an elevated privileged user to get the admin password of the device.

The Zyxel Multy X (AC3000 Tri-Band WiFi System) device doesn't use a suitable mechanism to protect the UART. After an attacker dismantles the device and uses a USB-to-UART cable to connect the device, he can use the 1234 password for the root account to login to the system. Furthermore, an attacker can start the device's TELNET service as a backdoor.

ZyXEL ZyWALL/USG series devices have a Bleichenbacher vulnerability in their Internet Key Exchange (IKE) handshake implementation used for IPsec based VPN connections.

ZyXEL P-660HW v3 devices allow remote attackers to cause a denial of service (router unreachable/unresponsive) via a flood of fragmented UDP packets.

This vulnerability allows remote attackers to cause a denial-of-service condition on vulnerable installations of ZyXEL P-870H-51 DSL Router 1.00(AWG.3)D5. Authentication is not required to exploit this vulnerability. The specific flaw exists within numerous exposed CGI endpoints. The vulnerability is caused by improper access controls that allow access to critical functions without authentication. An attacker can use this vulnerability to reboot affected devices, along with other actions. Was ZDI-CAN-4540.

Zyxel VMG1312-B10D devices before 5.13(AAXA.8)C0 allow ../ Directory Traversal, as demonstrated by reading /etc/passwd.

ZyXEL VMG3312-B10B 1.00(AAPP.7) devices have a backdoor root account with the tTn3+Z@!Sr0O+ password hash in the etc/default.cfg file.

Zyxel VMG3312 B10B devices are affected by a persistent XSS vulnerability via the pages/connectionStatus/connectionStatus-hostEntry.cmd hostname parameter.

A system command injection vulnerability in zyshclient in ZyXEL NSA325 V2 version 4.81 allows attackers to execute system commands via the web application API.

Missing protections against Cross-Site Request Forgery in the web application in ZyXEL NSA325 V2 version 4.81 allow attackers to perform state-changing actions via crafted HTTP forms.

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 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.

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 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.

ZyXEL ZyWALL USG 2.12 AQQ.2 and 3.30 AQQ.7 devices are affected by a CSRF vulnerability via a cgi-bin/zysh-cgi cmd action to add a user account. This account's access could, for example, subsequently be used for stored XSS.

A post-authentication command injection vulnerability in the CGI program in the Zyxel GS1900-48 switch firmware version V2.80(AAHN.1)C0 and earlier could allow an authenticated, LAN-based attacker with administrator privileges to execute some operating system (OS) commands on an affected device by sending a crafted HTTP request.

A buffer overflow vulnerability in the CGI program in the Zyxel GS1900-48 switch firmware version V2.80(AAHN.1)C0 and earlier could allow an authenticated, LAN-based attacker with administrator privileges to cause denial of service (DoS) conditions via a crafted URL.

An insufficient entropy vulnerability caused by the improper use of a randomness function with low entropy for web authentication tokens generation exists in the Zyxel GS1900-10HP firmware version V2.80(AAZI.0)C0. This vulnerability could allow a LAN-based attacker a slight chance to gain a valid session token if multiple authenticated sessions are alive.