Buffer overflow in Zyxel Gs1900-10hp Firmware

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.

Vulnerability class: Buffer Overflow

EPSS: 0.003 (24.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on . CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: .

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.

References

Frequently asked questions

What is CVE-2026-7273?
CVE-2026-7273 is a high-severity vulnerability in Zyxel Gs1900-10hp Firmware, classified under Stack-based Buffer Overflow. CVSS score: 8.8/10. Published 2026-06-16.
How severe is CVE-2026-7273?
High severity. CVSS v3 base score is 8.8 out of 10.
Is CVE-2026-7273 known to be exploited?
Yes. CVE-2026-7273 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-09-21), indicating it is being actively exploited.