CISA KEV: CVE-2026-7273 — Zyxel GS1900 Series Switches actively exploited

Zyxel GS1900 Series Switches Stack-Based Buffer Overflow Vulnerability. Zyxel GS1900 series switches contain a stack-based buffer overflow vulnerability in the CGI program which could allow a LAN-based, unauthenticated attacker to exploit the flaw and potentially execute OS commands via a crafted HTTP request. Required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance