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Vulnerabilities/CVE-2026-7273Public Intelligence Dossier
Source: zyxel · Limited verification•Last verified: •Collection Degraded
CVE-2026-7273ListedHIGH (raw)CVSS 8.8CWE-121

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.

Published: 16 Jun 2026•Last updated: 22 Sept 2026, 05:40 PM IST•Source identifier: security@zyxel.com.tw
Dossier completeness: source-provided sections 3 / 3 · rule guidance not available. Missing source facts count as incomplete.
Official source
CISA KEV catalog
Listed
Added21 Sept 2026
Due24 Sept 2026
RansomwareUnknown
CVSS score
8.8HIGH (raw)
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Metric sourcesecurity@zyxel.com.tw
EPSS probability
2.5%0.025
Percentile84th
Weakness type
CWE-121
No further CWE recorded
Remediation
Patch status unknown
No fixed version or KB recorded

Why It Matters

Analysis dossier

Why It Matters

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.

SOC priority

Immediate Attention

Actively exploited

Yes

Publicly disclosed

Unknown

Risk basis: CISA KEV exploitation signal; HIGH severity; Known exploitation signal from CISA KEV or ransomware metadata

Affected Products & Remediation

10 source-backed products
Affected products and versions (source)
  • zyxel gs1900-8 firmware · < 2.90\(aahh.2\)c0 · NVD CPE · Source
  • zyxel gs1900-8hp firmware · < 2.90\(aahi.2\)c0 · NVD CPE · Source
  • zyxel gs1900-10hp firmware · < 2.90\(aazi.2\)c0 · NVD CPE · Source
  • zyxel gs1900-16 firmware · < 2.90\(aahj.2\)c0 · NVD CPE · Source
  • zyxel gs1900-24 firmware · < 2.90\(aahl.2\)c0 · NVD CPE · Source
  • zyxel gs1900-24e firmware · < 2.90\(aahk.2\)c0 · NVD CPE · Source
  • zyxel gs1900-24ep firmware · < 2.90\(abto.2\)c0 · NVD CPE · Source
  • zyxel gs1900-24hpv2 firmware · < 2.90\(abtp.2\)c0 · NVD CPE · Source
  • zyxel gs1900-48 firmware · < 2.90\(aahn.2\)c0 · NVD CPE · Source
  • zyxel gs1900-48hpv2 firmware · < 2.90\(abtq.2\)c0 · NVD CPE · Source
NVD applicability prerequisites: cpe:2.3:h:zyxel:gs1900-8:-:*:*:*:*:*:*:*, cpe:2.3:h:zyxel:gs1900-8hp:-:*:*:*:*:*:*:*, cpe:2.3:h:zyxel:gs1900-10hp:-:*:*:*:*:*:*:*, cpe:2.3:h:zyxel:gs1900-16:-:*:*:*:*:*:*:*, cpe:2.3:h:zyxel:gs1900-24:-:*:*:*:*:*:*:*, cpe:2.3:h:zyxel:gs1900-24e:-:*:*:*:*:*:*:*, cpe:2.3:h:zyxel:gs1900-24ep:-:*:*:*:*:*:*:*, cpe:2.3:h:zyxel:gs1900-24hpv2:-:*:*:*:*:*:*:*, cpe:2.3:h:zyxel:gs1900-48:-:*:*:*:*:*:*:*, cpe:2.3:h:zyxel:gs1900-48hpv2:-:*:*:*:*:*:*:*. These are conditions, not proof that an environment is exposed or unaffected.
Recorded patch / KBNot provided by source

Vendor or catalog guidance (source)

  • CISA KEV: 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.

Known exploitation (source facts)

Only what a source states. Unknown means no source has said either way; it is not "not exploited".

CISA KEV
Listed
Exploited (source statement)
Yes
Publicly disclosed (source)
Unknown

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 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.

Suggested hunting (rule-based inference)

SecOps Signal recommendation (rule-based inference). These steps are hunting hypotheses from the vulnerability class; they do not state or imply that exploitation occurred here or anywhere.

No rule-based guidance for this vulnerability class

CISA KEV Record

Catalog entry
21 Sept 2026
Required action due
24 Sept 2026
Known ransomware use
Unknown

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.

Change History & Source Data

— No recorded material change

CNA / source
security@zyxel.com.tw
Record status · verification
UPDATED · CISA KEV confirmed
CPE
cpe:2.3:o:zyxel:gs1900-8_firmware:*:*:*:*:*:*:*:*, cpe:2.3:h:zyxel:gs1900-8:-:*:*:*:*:*:*:*, cpe:2.3:o:zyxel:gs1900-8hp_firmware:*:*:*:*:*:*:*:*, cpe:2.3:h:zyxel:gs1900-8hp:-:*:*:*:*:*:*:*, cpe:2.3:o:zyxel:gs1900-10hp_firmware:*:*:*:*:*:*:*:*, cpe:2.3:h:zyxel:gs1900-10hp:-:*:*:*:*:*:*:*, cpe:2.3:o:zyxel:gs1900-16_firmware:*:*:*:*:*:*:*:*, cpe:2.3:h:zyxel:gs1900-16:-:*:*:*:*:*:*:*, cpe:2.3:o:zyxel:gs1900-24_firmware:*:*:*:*:*:*:*:*, cpe:2.3:h:zyxel:gs1900-24:-:*:*:*:*:*:*:*

Evidence & Provenance

4 public sources
CISA KEV CatalogAdded 2026-09-21zyxel.comSource recordnvd.nist.govSource recordcisa.govSource record

Linked by the query's stored exact CVE association. Review required tables and validation status before use.

Detection Hunting Query
Target: DeviceTvmSoftwareVulnerabilities•Defender XDR
Detect endpoints exposed to CVE-2026-7273
Purpose: Exposure assessment (Category: Exposure Check)Why linked: Query metadata names CVE-2026-7273
DeviceTvmSoftwareVulnerabilities| where CveId == "CVE-2026-7273"| project DeviceId, DeviceName, OSPlatform, OSVersion, SoftwareVendor, SoftwareName, SoftwareVersion, CveId, VulnerabilitySeverityLevel, RecommendedSecurityUpdate, RecommendedSecurityUpdateId| sort by VulnerabilitySeverityLevel desc
Schema Checked · Not runtime validatedSource: SecOps Signal deterministic template · Limited verificationStatic screening: Passed structure and schema checks; tenant execution is not verified.
Open KQL Library

Correlated briefings

— No published briefing references this CVE

SecOps Signal surfaces public advisory facts only. A missing value means the source has not published it, not that your environment is unaffected. No tenant inventory is connected.