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Zyxel security advisory (AV26-603) – Update 1

Used in attacksCriticalCVSS 8.8Canadian Centre for Cyber Security · Canadian Centre for Cyber Security·

At a glance

Severity
CriticalCVSS 8.8
Used in attacks
Yes, 1 of 1 flaw named
Flaws named
CVE-2026-7273
Vendors and products
Zyxel
Industries
Government
Reported by
1 outlet

On June 16, 2026, Zyxel published a security advisory to address vulnerabilities in the following products:

  • GS1900 series switches – multiple versions and models

Update 1

On September 21, 2026, Cybersecurity and Infrastructure Security Agency (CISA) added CVE-2026-7273 to their Known Exploited Vulnerabilities (KEV) Database.

The Cyber Centre encourages users and administrators to review the provided web links and apply the necessary updates.

Originally published by Canadian Centre for Cyber Security. © Canadian Centre for Cyber Security. Written by Canadian Centre for Cyber Security.

Read at cyber.gc.ca ↗Official Source

Vulnerabilities referenced

  • CVE-2026-72738.8High

    Zyxel GS1900 Series Switches

    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.

    Used in attacks

    Added to CISA's list 2026-09-21 · Exploit code published · Patch or advisory available

    Full record →

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Coverage

One outlet has carried this so far.

  1. Canadian Centre for Cyber Security ↗Official SourceFirst reported

    2026-09-21 20:12 UTC

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