September 21, 2026 · Applied Cybernetics Group
CVE-2026-7273 — Zyxel GS1900 Series Switches
Zyxel GS1900 Series Switches Stack-Based Buffer Overflow Vulnerability
- Added to KEV
2026-09-21- Federal due date
2026-09-24- Vendor
- Zyxel
- Product
- GS1900 Series Switches
- EPSS
- 84.2th percentile (score 0.025, as of
2026-10-04) - NVD CVSS v3.1
- 8.8 (HIGH)
- Ransomware use
- Unknown
- Upstream
- https://nvd.nist.gov/vuln/detail/CVE-2026-7273
CISA short description
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.
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.
NVD description
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.