Zyxel security advisory for multiple vulnerabilities in NBG-418N v2 home router

Zyxel_May · May 2023

CVE: CVE-2023-22921, CVE-2023-22922, CVE-2023-22923, CVE-2023-22924

Summary

Zyxel has released a patch addressing multiple vulnerabilities in the NBG-418N v2 home router. Users are advised to install the patch for optimal protection.

What are the vulnerabilities?

CVE-2023-22921

A cross-site scripting (XSS) vulnerability could allow a remote authenticated attacker with administrator privileges to store malicious scripts using a web management interface parameter, resulting in denial-of-service (DoS) conditions on an affected device. Note that WAN access is disabled by default on the home router.

CVE-2023-22922

A buffer overflow vulnerability could allow a remote unauthenticated attacker to cause DoS conditions by sending crafted packets if Telnet is enabled on a vulnerable device. Note that WAN access is disabled by default on the home router.

CVE-2023-22923

A format string vulnerability in a binary could allow a remote authenticated attacker to cause DoS conditions on a vulnerable device. Note that WAN access is disabled by default on the home router.

CVE-2023-22924

A buffer overflow vulnerability could allow a remote authenticated attacker with administrator privileges to cause DoS conditions by executing crafted CLI commands on a vulnerable device. Note that WAN access is disabled by default on the home router.

What versions are vulnerable—and what should you do?

After a thorough investigation, we’ve identified only one vulnerable product that is within the vulnerability support period and released a firmware patch to address the issue, as shown in the table below.

Affected model	Affected version	Patch availability
NBG-418N v2	V1.00(AARP.13)C0 and earlier	V1.00(AARP.14)C0

Got a question?

Please contact your local service rep or visit Zyxel’s Community for further information or assistance.

Acknowledgment

Thanks to Toni Koivunen from Fitsec Ltd. for reporting the issues to us.

Revision history

2023-5-2: Initial release.