CVE-2023-27992: Zyxel Multiple NAS Devices Command Injection Vulnerability

How to check if you are exposed to CVE-2023-27992

1. Find every Zyxel Multiple Network-Attached Storage (NAS) Devices system you or your clients run, including ones exposed to the internet. Those come first: CISA only lists flaws attackers are already using.
2. Compare each version with the fixed versions in the vendor advisory below. Where no fix exists yet, apply the vendor’s mitigation or take the system off the internet.
3. Run a credentialed vulnerability scan to catch the systems you missed, then check that the next scan no longer reports CVE-2023-27992.

US federal agencies had to fix this by 2023-07-14. Everyone else should treat that deadline as a guide: if it has passed, this is overdue.

Timeline

1. 2023-06-23 · Added to CISA's Known Exploited Vulnerabilities catalog
2. 2023-07-14 · Fix-by date for US federal agencies, passed 1,206 days ago

Vendor advisories and fixes

• https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-pre-authentication-command-injection-vulnerability-in-nas-products

Weakness type

• CWE-78

More exploited Zyxel vulnerabilities

CISA lists 13 exploited Zyxel vulnerabilities. The closest matches:

• CVE-2020-9054Zyxel Multiple NAS Devices OS Command Injection VulnerabilityAdded 2022-03-25
• CVE-2026-7273Zyxel GS1900 Series Switches Stack-Based Buffer Overflow VulnerabilityAdded 2026-09-21
• CVE-2024-40891Zyxel DSL CPE OS Command Injection VulnerabilityAdded 2025-02-11
• CVE-2024-40890Zyxel DSL CPE OS Command Injection VulnerabilityAdded 2025-02-11
• CVE-2024-11667Zyxel Multiple Firewalls Path Traversal VulnerabilityAdded 2024-12-03
• CVE-2017-6884Zyxel EMG2926 Routers Command Injection VulnerabilityAdded 2023-09-18
• CVE-2017-18368Zyxel P660HN-T1A Routers Command Injection VulnerabilityAdded 2023-08-07
• CVE-2023-33010Zyxel Multiple Firewalls Buffer Overflow VulnerabilityAdded 2023-06-05

Keep going

• All exploited CVEs
• Check another CVE
• What is CISA KEV?
• What is EPSS?

Sources: CISA Known Exploited Vulnerabilities catalog (version 2026.10.30); EPSS data from FIRST.org; CVSS and descriptions from the NIST National Vulnerability Database. Checked 2026-11-01. This product uses the NVD API but is not endorsed or certified by the NVD.