CVE intelligenceCISA KEV

CVE-2026-7273

Zyxel GS1900 Series Switches Stack-Based Buffer Overflow Vulnerability

Published Jun 16, 2026Sources checked Oct 3, 2026

8.8HIGHCVSS out of 10

What this means

Actively exploited

CISA lists CVE-2026-7273 in its Known Exploited Vulnerabilities catalog, which means exploitation has been observed. The entry applies to Zyxel GS1900 Series Switches.

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.

CISA KEVListedObserved exploitation

EPSS2.5%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors1Source-linked actor relationships

Overview

What is CVE-2026-7273?

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.