Verified reference description
The following technical description is credited to the CISA KEV dataset (CC0):
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.
Record and timeline
- Product: Zyxel — GS1900 Series Switches
- Identifier: CVE-2026-7273
- CVE record published: 2026-06-16
- Added to CISA KEV: 2026-09-21
- Reference score: 8.8/10, CVSS 3.1; provider: Zyxel
- Weakness class: CWE-121
A KEV addition date is not a discovery date. CVSS describes technical severity; actual exposure and asset importance also influence remediation priority.
Defensive next steps
Match the installed Zyxel GS1900 Series Switches version and configuration against the linked technical advisory. Apply the manufacturer-approved fixed release or an explicitly documented mitigation; this profile does not guess a fixed version. Verify the patch and review relevant logs afterward. Plan a supported replacement where the product is end-of-life.
Scope and limitations
This is an awareness and defensive-prioritization profile, not a penetration test or a finding that your network is compromised. KEV membership indicates evidence of real-world exploitation. Mandatory CISA deadlines apply to entities covered by the relevant directive, not universally to every reader.
Reported versions and platforms
The table shows up to ten structured version entries from the official CVE-2026-7273 record. Original field names and values are retained deliberately. This is not an automated exposure verdict or a complete list of every product branch; use the full record and vendor advisory for a deployment decision.
| Product in record | Platform | Version fields — original values | Record status |
|---|---|---|---|
| Zyxel — GS1900-48HPv2 firmware | — | version=<= 2.90(ABTQ.1)C0 | affected |
| Zyxel — GS1900-8 firmware | — | version=<= 2.90(AAHH.1)C0 | affected |
| Zyxel — GS1900-8HP firmware | — | version=<= 2.90(AAHI.1)C0 | affected |
| Zyxel — GS1900-10HP firmware | — | version=<= 2.90(AAZI.1)C0 | affected |
| Zyxel — GS1900-16 firmware | — | version=<= 2.90(AAHJ.1)C0 | affected |
| Zyxel — GS1900-24 firmware | — | version=<= 2.90(AAHL.1)C0 | affected |
| Zyxel — GS1900-24E firmware | — | version=<= 2.90(AAHK.1)C0 | affected |
| Zyxel — GS1900-24EP firmware | — | version=<= 2.90(ABTO.1)C0 | affected |
| Zyxel — GS1900-24HPv2 firmware | — | version=<= 2.90(ABTP.1)C0 | affected |
| Zyxel — GS1900-48 firmware | — | version=<= 2.90(AAHN.1)C0 | affected |
Full record and technical references
Turn the record into an operational decision
For Zyxel GS1900 Series Switches, record the asset, effective version, enabled feature and access path. When the reference does not map clearly to your package or branch, retain an explicit unknown status and assign follow-up rather than guessing that the system is safe.
After remediation, record the effective running version, health-check outcome and change time, not merely installation success. Evidence of compromise requires the appropriate incident-response workflow; this page does not diagnose any network as compromised or clean.
Scoring vector and scope
Vector recorded by the reference: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS is owned by FIRST and used by permission. The reference score is not a substitute for organizational risk assessment. Version data comes from the record retrieved for this review and may change when sources are updated.
