CVE-2026-7273
Zyxel GS1900 Series Switches Stack-Based Buffer Overflow Vulnerability
IN CISA KEV
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.
- Vendor
- Zyxel
- Product
- GS1900 Series Switches
- CVSS 3.1
- 8.8 (high), scored by security@zyxel.com.twCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CWE
- CWE-121
- Published
- 2026-06-16
- NVD modified
- 2026-09-22
- NVD status
- Analyzed
CISA KEV
- Date added
- 2026-09-21
- Due date
- 2026-09-24
- Ransomware use
- Unknown
- 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.
EPSS
2.50% chance of exploitation in the next 30 days (percentile 84th)
FIRST EPSS, updated 17 Oct 2026. About EPSS
CVSS is severity, EPSS is likelihood, KEV means already exploited. EPSS is a statistical probability, not a certainty: a low score does not make a bug safe, and a high one does not prove it is being exploited.
References
- www.zyxel.com (Vendor Advisory)
- www.cisa.gov (Third Party Advisory, US Government Resource)
Data last updated 18 Oct 2026. Sources: NVD API 2.0, CISA KEV catalog, FIRST EPSS. Links: NVD, CISA KEV. Metadata only. ThreatWire does not host exploit code.