The diagnostic-ping implementation on ZyXEL PMG5318-B20A devices with firmware before 1.00(AANC.2)C0 allows remote attackers to execute arbitrary commands via the PingIPAddr parameter.

Belkin F9K1102 2 devices with firmware 2.10.17 rely on client-side JavaScript code for authorization, which allows remote attackers to obtain administrative privileges via certain changes to LockStatus and LoginSuccess values.

ZyXEL P-660HW-T1 2 devices with ZyNOS firmware 3.40(AXH.0), PMG5318-B20A devices with firmware 1.00AANC0b5, and NBG-418N devices have a default password of 1234 for the admin account, which allows remote attackers to obtain administrative access via unspecified vectors.

Cisco NX-OS 6.0(2)U6(1) through 6.0(2)U6(5) on Nexus 3000 devices and 6.0(2)A6(1) through 6.0(2)A6(5) and 6.0(2)A7(1) on Nexus 3500 devices has hardcoded credentials, which allows remote attackers to obtain root privileges via a (1) TELNET or (2) SSH session, aka Bug ID CSCuy25800.

WiMAX routers based on the MediaTek SDK (libmtk) that use a custom httpd plugin are vulnerable to an authentication bypass allowing a remote, unauthenticated attacker to gain administrator access to the device by performing an administrator password change on the device via a crafted POST request.

The ZyXEL P-660HW series router has "admin" as its default password, which allows remote attackers to gain administrative access.

The ZyXEL P-660HW series router maintains authentication state by IP address, which allows remote attackers to bypass authentication by establishing a session from a source IP address of a previously authenticated user.

Zyxel WRE6505 devices have a default TELNET password of 1234 for the root and admin accounts, which makes it easier for remote attackers to conduct DNS hijacking attacks by reconfiguring the built-in dnshijacker process.

An issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0. Due to lack of input validation in the cmdsystracerouteexec(), cmdsysarpclear(), and cmdsyspingexec() functions in the libclicmd.so library contained in the firmware, an attacker could leverage these functions to call system() and execute arbitrary commands on the switches. (Note that these functions are currently not called in this version of the firmware, however an attacker could use other vulnerabilities to finally use these vulnerabilities to gain code execution.)

Zyxel VMG5313-B30B router on firmware 5.13(ABCJ.6)b31127, and possibly older versions of firmware are affected by insecure permissions which allows regular and other users to create new users with elevated privileges. This is done by changing "FirstIndex" field in JSON that is POST-ed during account creation. Similar may also be possible with account deletion.

Zyxel CloudCNM SecuManager 3.1.0 and 3.1.1 allows use of live/CPEManager/AXCampaignManager/deletecpesbyids?cpeids= for eval injection of Python code.

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.

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.

A command injection vulnerability in the web interface of the Zyxel NWA-1100-NH firmware could allow an attacker to execute arbitrary OS commands on the device.

UNSUPPORTED WHEN ASSIGNED The command injection vulnerability in the “setCookie” parameter in Zyxel NAS326 firmware versions before V5.21(AAZF.17)C0 and NAS542 firmware versions before V5.21(ABAG.14)C0 could allow an unauthenticated attacker to execute some operating system (OS) commands by sending a crafted HTTP POST request.

UNSUPPORTED WHEN ASSIGNED The command injection vulnerability in the CGI program "remotehelp-cgi" in Zyxel NAS326 firmware versions before V5.21(AAZF.17)C0 and NAS542 firmware versions before V5.21(ABAG.14)C0 could allow an unauthenticated attacker to execute some operating system (OS) commands by sending a crafted HTTP POST request.

UNSUPPORTED WHEN ASSIGNED The remote code execution vulnerability in the CGI program “fileupload-cgi” in Zyxel NAS326 firmware versions before V5.21(AAZF.17)C0 and NAS542 firmware versions before V5.21(ABAG.14)C0 could allow an unauthenticated attacker to execute arbitrary code by uploading a crafted configuration file to a vulnerable device.

UNSUPPORTED WHEN ASSIGNED A command injection vulnerability in the functions formSysCmd(), formUpgradeCert(), and formDelcert() in the Zyxel NWA1100-N firmware version 1.00(AACE.1)C0 could allow an unauthenticated attacker to execute some OS commands to access system files on an affected device.

The improper neutralization of special elements in the parameter "host" in the CGI program of Zyxel NWA1123ACv3 firmware version 6.70(ABVT.4) and earlier, WAC500 firmware version 6.70(ABVS.4)

and earlier, WAX655E firmware version 7.00(ACDO.1) and earlier, WBE530 firmware version 7.00(ACLE.1)

and earlier, and USG LITE 60AX firmware version V2.00(ACIP.2) could allow an unauthenticated attacker to execute OS commands by sending a crafted cookie to a vulnerable device.

UNSUPPORTED WHEN ASSIGNED A command injection vulnerability in the export-cgi program of Zyxel NAS326 firmware versions through V5.21(AAZF.18)C0 and NAS542 firmware versions through V5.21(ABAG.15)C0 could allow an unauthenticated attacker to execute some operating system (OS) commands by sending a crafted HTTP POST request.

A buffer overflow vulnerability in the notification 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 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.

Zyxel ATP, USG FLEX, VPN, and ZyWALL/USG firewalls allow for improper error message handling which could allow an unauthenticated attacker to execute OS commands remotely by sending crafted packets to an affected device.

A directory traversal vulnerability in the web management interface of Zyxel ATP series firmware versions V5.00 through V5.38, USG FLEX series firmware versions V5.00 through V5.38, USG FLEX 50(W) series firmware versions V5.10 through V5.38, and USG20(W)-VPN series firmware versions V5.10 through V5.38 could allow an attacker to download or upload files via a crafted URL.

UNSUPPORTED WHEN ASSIGNED Insecure default credentials for the Telnet function in the legacy DSL CPE Zyxel VMG4325-B10A firmware version 1.00(AAFR.4)C020170615 could allow an attacker to log in to the management interface if the administrators have the option to change the default credentials but fail to do so.

A buffer overflow vulnerability in the URL parser of the zhttpd web server in Zyxel VMG8825-T50K firmware versions prior to V5.50(ABOM.5)C0 could allow an unauthenticated attacker to cause denial-of-service (DoS) conditions and potentially execute arbitrary code by sending a specially crafted HTTP request.

A command injection vulnerability in the UPnP function of the Zyxel EX3510-B0 firmware versions through 5.17(ABUP.15.1)C0 could allow a remote attacker to execute operating system (OS) commands on an affected device by sending specially crafted UPnP SOAP requests.

A OS command injection vulnerability in the CGI program of Zyxel USG FLEX 100(W) firmware versions 5.00 through 5.21 Patch 1, USG FLEX 200 firmware versions 5.00 through 5.21 Patch 1, USG FLEX 500 firmware versions 5.00 through 5.21 Patch 1, USG FLEX 700 firmware versions 5.00 through 5.21 Patch 1, USG FLEX 50(W) firmware versions 5.10 through 5.21 Patch 1, USG20(W)-VPN firmware versions 5.10 through 5.21 Patch 1, ATP series firmware versions 5.10 through 5.21 Patch 1, VPN series firmware versions 4.60 through 5.21 Patch 1, which could allow an attacker to modify specific files and then execute some OS commands on a vulnerable device.

Multiple ZyXEL network-attached storage (NAS) devices running firmware version 5.21 contain a pre-authentication command injection vulnerability, which may allow a remote, unauthenticated attacker to execute arbitrary code on a vulnerable device. ZyXEL NAS devices achieve authentication by using the weblogin.cgi CGI executable. This program fails to properly sanitize the username parameter that is passed to it. If the username parameter contains certain characters, it can allow command injection with the privileges of the web server that runs on the ZyXEL device. Although the web server does not run as the root user, ZyXEL devices include a setuid utility that can be leveraged to run any command with root privileges. As such, it should be assumed that exploitation of this vulnerability can lead to remote code execution with root privileges. By sending a specially-crafted HTTP POST or GET request to a vulnerable ZyXEL device, a remote, unauthenticated attacker may be able to execute arbitrary code on the device. This may happen by directly connecting to a device if it is directly exposed to an attacker. However, there are ways to trigger such crafted requests even if an attacker does not have direct connectivity to a vulnerable devices. For example, simply visiting a website can result in the compromise of any ZyXEL device that is reachable from the client system. Affected products include: NAS326 before firmware V5.21(AAZF.7)C0 NAS520 before firmware V5.21(AASZ.3)C0 NAS540 before firmware V5.21(AATB.4)C0 NAS542 before firmware V5.21(ABAG.4)C0 ZyXEL has made firmware updates available for NAS326, NAS520, NAS540, and NAS542 devices. Affected models that are end-of-support: NSA210, NSA220, NSA220+, NSA221, NSA310, NSA310S, NSA320, NSA320S, NSA325 and NSA325v2

The web management interface on Belkin F9K1102 2 devices with firmware 2.10.17 has a blank password, which allows remote attackers to obtain administrative privileges by leveraging a LAN session.