Descripción
Los switches Zyxel GS1900 series contienen una vulnerabilidad de desbordamiento de búfer en la pila en el programa CGI que podría permitir a un atacante no autenticado con acceso a la LAN explotar la falla y potencialmente ejecutar comandos del sistema operativo mediante una solicitud HTTP especialmente manipulada.
Acción recomendada
Aplicar las mitigaciones del fabricante y revisar los equipos afectados en busca de señales de compromiso (triaje forense) antes de darlos por remediados. Evaluar la exposición a internet de cada activo para priorizar la aplicación de parches. En servicios en la nube, seguir las recomendaciones de seguridad del proveedor; si no hay mitigaciones disponibles, discontinuar el uso del producto.
Referencia de CISA para agencias federales de EE. UU.: BOD 26-04.
Referencias
- Aviso de zyxel.com zyxel.com/global/en/support/security-advisories/zyxel-security-adviso…
- BOD 26-04 cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updat…
- Requisitos de triaje forense cisa.gov/news-events/directives/bod-26-04-implementation-guidance-pri…
- Ficha en NVD (NIST) nvd.nist.gov/vuln/detail/CVE-2026-7273
Ver el texto original en inglés (CISA)
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 and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
Notes: 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 ; ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-7273
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