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Buffer overflow vulnerability in Zyxel

Indian – Computer Emergency Response Team (https://www.cert-in.org.in)

Severity Rating: HIGH

Software Affected

Zyxel GS1900-8 version 2.90(AAHH.1)C0 and earlier

Zyxel GS1900-8HP version 2.90(AAHI.1)C0 and earlier

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

Overview

Buffer overflow vulnerability has been reported in Zyxel which could allow an attacker to execute arbitrary operating system commands on the targeted system.

Target Audience:

All end-user organizations and individuals using Zyxel.

Risk Assessment:

High risk of remote code execution.

Impact Assessment:

Potential for remote code execution.

Description

Zyxel is a networking equipment manufacturer that provides switches, routers, firewalls, wireless access points, and other network infrastructure solutions for businesses and consumers.

A vulnerability has been reported in Zyxel Communications GS1900 series switches due to a stack-based buffer overflow vulnerability in the CGI program of the switch firmware. A LAN-based, unauthenticated attacker could exploit this vulnerability to send specially crafted HTTP requests to vulnerable devices and potentially execute OS commands on the targeted system.

Successful exploitation of this vulnerability could allow an attacker to execute arbitrary operating system commands on the targeted system.

Solution

Apply appropriate updates as mentioned by the vendor:

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

Vendor Information

Zyxel

https://www.zyxel.com/

References

 

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

CVE Name

CVE-2026-7273

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Thanks and Regards,

CERT-In

Incident Response Help Desk

e-mail: incident@cert-in.org.in

Phone: +91-11-22902657

Toll Free Number: 1800-11-4949

Toll Free Fax : 1800-11-6969

Web: http://www.cert-in.org.in

PGP Fingerprint: A768 083E 4475 5725 B81A A379 2156 C0C0 B620 D0B4

PGP Key information:

https://www.cert-in.org.in/s2cMainServlet?pageid=CONTACTUS

Postal address:

Indian Computer Emergency Response Team (CERT-In)

Ministry of Electronics and Information Technology

Government of India

Electronics Niketan

6, C.G.O. Complex

New Delhi-110 003

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