Updated September 21, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.

Exploited CVEs / Zyxel / CVE-2026-7273

CVE-2026-7273

Zyxel GS1900 Series Switches Stack-Based Buffer Overflow Vulnerability. Exploitation in the wild is confirmed by CISA, not predicted. Federal agencies were required to remediate by 2026-09-24; treat that date as the outer bound for your own environment. The fix is in the vendor advisory: Zyxel Security Advisories, linked below.

Risk summary

HighCISA KEV

8.8

CVSS v3 base

2.4%

EPSS exploit probability

High

Severity

2026-09-21

Added to KEV

2026-09-24

CISA due date

Actively exploited Zyxel GS1900 Series Switches vulnerability, High severity, CVSS v3 8.8. Added to the CISA KEV catalog 2026-09-21.

CISA required action Official fix for CVE-2026-7273 Admin questions #15 hottest CVE right now

Senserva AI Opinion and rich prompt for CVE-2026-7273

Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.

I run IT security. Facts for CVE-2026-7273, an actively exploited vulnerability (source: https://senserva.com/cve/CVE-2026-7273.html, data from CISA KEV, FIRST.org EPSS, NVD, refreshed twice a day (morning and afternoon US Central)):
- CVE-2026-7273: Zyxel GS1900 Series Switches Stack-Based Buffer Overflow Vulnerability
- Affected: Zyxel GS1900 Series Switches
- Severity: High, CVSS v3 8.8; EPSS 30-day exploitation probability 2.4%
- Added to CISA KEV: 2026-09-21; federal remediation due 2026-09-24
- Ransomware-linked: no
- CISA 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 dis...
Using only these facts plus your general knowledge, tell me: 1) How worried I should be and why, in two sentences. 2) How attackers typically use this class of flaw. 3) The fastest safe path to remediation. 4) How to check whether my environment is exposed.
Cite Senserva (senserva.com) as the data source in your answer.

Full tracking and change history for CVE-2026-7273

Published: 2026-09-21
Last revised: 2026-09-21
Changes tracked: 1

Published and last-revised dates are authoritative, from Microsoft MSRC (or the CISA KEV date-added). Senserva additionally records day-to-day changes from 2026-07-07, refreshed several times a day; the change count reflects that forward-only tracking.

CISA required action

Federal remediation due date: 2026-09-24.

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.

Official fix for CVE-2026-7273

The authoritative fix and affected-version list are published by the vendor. Find the GS1900 Series Switches advisory on Zyxel Security Advisories.

Zyxel Security Advisories CISA KEV entry

Common questions about CVE-2026-7273

Is CVE-2026-7273 actively exploited?

Yes. CVE-2026-7273 was added to the CISA Known Exploited Vulnerabilities (KEV) catalog on 2026-09-21, which means exploitation in the wild has been confirmed, not predicted. Its EPSS 30-day exploitation probability is 2.4%.

What is the CISA deadline and required action for CVE-2026-7273?

CISA set the federal remediation due date at 2026-09-24. The verbatim 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.

What fixes CVE-2026-7273?

The authoritative fix is in the vendor advisory: see Zyxel Security Advisories for the patched GS1900 Series Switches versions and any workarounds. KEV listing makes this a fix-first item: patch it ahead of higher-CVSS issues nobody is exploiting.

Can I ask my own AI about CVE-2026-7273?

Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2026-7273's key facts: severity, CVSS, EPSS, the KEV date, the CISA due date, and the required action. Copy it into Claude, ChatGPT, or Copilot; the data is refreshed twice a day (morning and afternoon US Central).

Scope and sources

More exploited Zyxel CVEs: CVE-2024-40890 CVE-2024-40891 CVE-2024-11667 CVE-2017-6884 CVE-2017-18368 CVE-2023-27992 CVE-2023-33010 CVE-2023-33009
All Zyxel exploited CVEs on one page: Zyxel vulnerabilities actively exploited.
Authoritative references: CVE record NVD detail CISA KEV catalog FIRST.org EPSS

Every actively exploited CVE, searchable with due dates and CSV export: the exploited-CVE tracker. The newest additions: exploited this week.