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CVE-2026-7273

8.8, high Known exploited

Zyxel GS1900 Series Switches Stack-Based Buffer Overflow Vulnerability

NVD (opens in a new tab) CVE.org (opens in a new tab) CISA KEV catalogue (opens in a new tab)
CVSS
8.8, high high CVSS v3.1
EPSS, next 30 days
3% higher than 84.4% of scored CVEs
Exploitation
Confirmed in the wild
Published
16 Jun 20264 months ago

Known exploited

CISA added this to the Known Exploited Vulnerabilities Catalog on 21 Sept 2026. US federal agencies had to remediate by 24 Sept 2026, a deadline that has passed.

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.

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.

Details

Vendor
Zyxel
Product
GS1900-48HPv2 firmware
Weakness
CWE-121 (opens in a new tab)
Status
Analyzed
Updated
22 Sept 2026
Assigner
security@zyxel.com.tw

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References 3

Exploit code 1

Advisories 2

The kind is read from NVD's tags where present and from the shape of the URL otherwise, so treat it as a hint.

Other Zyxel CVEs

Every Zyxel CVE we hold

Same vendor in what we hold, not a known link between the flaws.

  • CVE-2024-40890 Zyxel DSL CPE OS Command Injection Vulnerability KEV EPSS 21% 8.8, high
  • CVE-2024-40891 Zyxel DSL CPE OS Command Injection Vulnerability KEV EPSS 22% 8.8, high
  • CVE-2024-11667 Zyxel Multiple Firewalls Path Traversal Vulnerability KEV EPSS 3% 9.8, critical
  • CVE-2023-27992 Zyxel Multiple NAS Devices Command Injection Vulnerability KEV EPSS 83% 9.8, critical
  • CVE-2023-33009 Zyxel Multiple Firewalls Buffer Overflow Vulnerability KEV EPSS 28% 9.8, critical
  • CVE-2023-33010 Zyxel Multiple Firewalls Buffer Overflow Vulnerability KEV EPSS 29% 9.8, critical
  • CVE-2023-28771 Zyxel Multiple Firewalls OS Command Injection Vulnerability KEV EPSS 99% 9.8, critical
  • CVE-2022-30525 Zyxel Multiple Firewalls OS Command Injection Vulnerability KEV EPSS 100% 9.8, critical

Beyond this page

Is CVE-2026-7273 in your network?

This page tells you how dangerous CVE-2026-7273 is out there. Whether it sits on one of your devices, only a scan of your own network can tell. That is what our systems do, every day, for the companies we protect.

CVE-2026-7273 is in the CISA catalogue of exploited vulnerabilities: attackers are already exploiting it.

  • EXYS7600 OCELOT

    Find it before attackers do

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  • EXYS7950 KONDRA

    Detect it if it's exploited

    Until the patch is applied, Kondra monitors your network, events and endpoints in real time. It keeps an inventory of the software installed on every endpoint, and its anomaly detection rules flag what an attacker does once inside.

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Check your exposure

Assembled from the NVD 2.0 API, the CISA Known Exploited Vulnerabilities Catalog and FIRST EPSS. Scores are as of our last collection on 17 Oct 2026, not the live upstream state.