CVE Catalog

Actively exploited in the wild

Zyxel GS1900 Series Switches Stack-Based Buffer Overflow Vulnerability

Zyxel - GS1900 Series Switches · Listed in the CISA KEV since 2026-09-21. This indicates confirmed attacks in production environments.

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.

CVE-2026-7273

HighCVSS 8.8KEV
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

High risk
1.99%

80th percentile - higher than 80% of all known CVEs

Summary

A stack-based buffer overflow vulnerability in the CGI program of Zyxel GS1900-48HPv2 firmware versions through 2.90(ABTQ.1)C0 could allow a LAN-based, unauthenticated attacker to exploit the flaw and potentially execute OS commands via a crafted HTTP request.

Risk Assessment

This vulnerability poses a risk of unauthorized access to the system, which could lead to serious security breaches within the organization.

Recommendation

It is recommended to update the firmware to the latest version to mitigate this vulnerability and to monitor network traffic for potential attack attempts.

Related vulnerabilities

Original NVD description (English source)

A stack-based buffer overflow vulnerability in the CGI program of Zyxel GS1900-48HPv2 firmware versions through 2.90(ABTQ.1)C0 could allow a LAN-based, unauthenticated attacker to exploit the flaw and potentially execute OS commands via a crafted HTTP request.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS