Zyxel GS1900 Series Switches Stack-Based Buffer Overflow Vulnerability

Are you affected?

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• cpe zyxel/gs1900-10hp firmwareversion unspecified
• cpe zyxel/gs1900-16 firmwareversion unspecified
• cpe zyxel/gs1900-24 firmwareversion unspecified
• cpe zyxel/gs1900-24e firmwareversion unspecified
• cpe zyxel/gs1900-24ep firmwareversion unspecified
• cpe zyxel/gs1900-24hpv2 firmwareversion unspecified
• cpe zyxel/gs1900-48 firmwareversion unspecified
• cpe zyxel/gs1900-48hpv2 firmwareversion unspecified
• cpe zyxel/gs1900-8 firmwareversion unspecified
• cpe zyxel/gs1900-8hp firmwareversion unspecified
• vendor Zyxel GS1900 Series Switchesversion unspecified

How to fix CVE-2026-7273

• Recommended remediation

  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 due date Sep 24, 2026.

• Official advisories

  • CISA KEV · cisa.gov
  • CVE.org · cve.org
  • FIRST EPSS · first.org
  • NIST NVD · nvd.nist.gov
  • VulnCheck KEV · vulncheck.com

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

1. Jun 15, 2026 · Catalog

   Detected

   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.

2. Sep 21, 2026 · CISA KEV

   Known exploited

   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

3. Sep 22, 2026 · Catalog

   Updated

   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.

4. Sep 24, 2026 · CISA KEV

   Remediation due

   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

Sources

• CISA KEVConfirmed exploitationCVE-2026-7273

  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.

  cisa.gov
• CVE.orgVulnerability recordCVE-2026-7273

  Official CVE identifier

  cve.org
• FIRST EPSSExploitation probabilityCVE-2026-7273

  30-day exploitation probability 2.5%

  first.org
• NIST NVDVulnerability recordCVE-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.

  nvd.nist.gov
• VulnCheck KEVConfirmed exploitationCVE-2026-7273

  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.

  vulncheck.com

References

• CISA note · nvd.nist.gov
• Third Party Advisory · cisa.gov
• CISA note · cisa.gov
• CISA note · cisa.gov
• VulnCheck exploitation evidence · cisa.gov
• Exploit · greynoise.io
• CISA note · zyxel.com

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.