Posting Date: 2026/10/05

【Vulnerability Alert】High-Risk Security Vulnerability in Zyxel GS1900 Series Switches (CVE-2026-7273), Please Verify and Patch Promptly

Subject:【Vulnerability Alert】High-Risk Security Vulnerability in Zyxel GS1900 Series Switches (CVE-2026-7273), Please Verify and Patch Promptly

Description:
- Forwarded NISAC Cybersecurity Message Alert NISAC-200-202610-00000003
- Researchers have discovered a stack-based buffer overflow vulnerability (CVE-2026-7273) in Zyxel GS1900 series switches. An unauthenticated LAN attacker may trigger memory corruption by sending a specially crafted HTTP request to the CGI program, thereby executing operating system commands on affected devices. This vulnerability has already been exploited by attackers. Please verify and patch promptly.
Affected Platforms:
- Zyxel GS1900-10HP version 2.90(AAZI.1)C0 and earlier
- Zyxel GS1900-16 version 2.90(AAHJ.1)C0 and earlier
- Zyxel GS1900-24 version 2.90(AAHL.1)C0 and earlier
- Zyxel GS1900-24E version 2.90(AAHK.1)C0 and earlier
- Zyxel GS1900-24EP version 2.90(ABTO.1)C0 and earlier
- Zyxel GS1900-24HPv2 version 2.90(ABTP.1)C0 and earlier
- Zyxel GS1900-48 version 2.90(AAHN.1)C0 and earlier
- Zyxel GS1900-48HPv2 version 2.90(ABTQ.1)C0 and earlier
- Zyxel GS1900-8 version 2.90(AAHH.1)C0 and earlier
- Zyxel GS1900-8HP version 2.90(AAHI.1)C0 and earlier
Recommended Actions:
- The vendor has released a patch or update for the vulnerability, please refer to the vendor's instructions for remediation; URL is as follows: https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-stack-based-buffer-overflow-vulnerability-in-gs1900-series-switches-06-16-2026
References:
1. https://nvd.nist.gov/vuln/detail/CVE-2026-7273
2. https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-stack-based-buffer-overflow-vulnerability-in-gs1900-series-switches-06-16-2026

Computer and Communication Center
Network System Division