CVE-2026-7273: 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.
- Published by source
- 2026-09-21
- First seen by Reality Radar
- 2026-10-20
- Last verified
- 2026-10-20
Affected
- Manufacturer
- Zyxel
- Products
- GS1900 Series Switches Zyxel GS1900 Series Switches
Whether your exact unit is affected depends on the model, serial number and region in the official notice.
What the official notice says
Risk: Actively exploited in the wild
Remedy / actions:
- 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.
Is this affecting you?
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Sources
- CISA Known Exploited Vulnerabilities Tier A · official published 2026-09-21
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