CVE-2026-7273

Zyxel GS1900 Series Switches command injection, confirmed exploited in the wild.

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.

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2.7%chance of exploitation in the next 30 days (EPSS), 86th percentile

21 Sepadded to CISA's Known Exploited Vulnerabilities list, 2026

24 Sepfederal remediation deadline, already passed

Passedpast the deadline: patch now

CISA's name for it	Zyxel GS1900 Series Switches Stack-Based Buffer Overflow Vulnerability
Vendor and product	Zyxel · GS1900 Series Switches
Type	command injection · CWE-121
Exploited	Confirmed by CISA listed 21 September 2026
Likelihood	more likely to be exploited than most
Deadline	24 September 2026 · already passed
Used in ransomware	Not reported
Advisories	www.zyxel.com ↗ · www.cisa.gov ↗ · www.cisa.gov ↗ · nvd.nist.gov ↗

What to do

Three steps, in this order

Step 1

Apply the vendor fix; command injection on an exposed device is used within days of disclosure.

Step 2

Restrict the management interface to a trusted network until the fix is in.

Step 3

Review the device's logs and configuration for changes you did not make.

CISA's 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.

CISA's 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.

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Questions

CVE-2026-7273 in short

Is CVE-2026-7273 being exploited?

Yes. CISA added CVE-2026-7273 to its Known Exploited Vulnerabilities catalogue on 21 September 2026, which it does only on evidence of exploitation in the wild.

What is the CISA deadline for CVE-2026-7273?

US federal agencies must remediate it by 24 September 2026. Everyone else should treat that date as the latest safe point to patch an internet-facing system.

How likely is CVE-2026-7273 to be exploited in the next 30 days?

FIRST's Exploit Prediction Scoring System gives it 2.7%, the 86th percentile of every CVE it scores.

How do I fix CVE-2026-7273?

Apply the vendor fix; command injection on an exposed device is used within days of disclosure. Restrict the management interface to a trusted network until the fix is in. Review the device's logs and configuration for changes you did not make.

Sources: CISA Known Exploited Vulnerabilities catalogue (released 10 November 2026) and FIRST EPSS. Page compiled automatically by SAK T.L.M, the threat-intelligence tool of SAK T.E.C, on 13 November 2026.