CVE-2026-7273

Unauthenticated OS command execution via CGI buffer overflow

Published Jun 16, 2026 · Updated Jun 16, 2026

Stack-based buffer overflow in Zyxel GS1900 series firmware allows remote attackers on the LAN to execute OS commands via HTTP. Zyxel identifies the locus only as the CGI program and has not disclosed the affected endpoint, request field, or unsafe copy operation. Exploitation requires LAN access but no authentication or user interaction, and successful memory corruption grants command execution on the switch.

CVSS severity8.8
High
EPSS probability0.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack-based buffer overflow in Zyxel GS1900 series firmware allows remote attackers on the LAN to execute OS commands via HTTP. Zyxel identifies the locus only as the CGI program and has not disclosed the affected endpoint, request field, or unsafe copy operation. Exploitation requires LAN access but no authentication or user interaction, and successful memory corruption grants command execution on the switch.

The record

CVE
CVE-2026-7273
Published
Jun 16, 2026
Updated
Jun 16, 2026
Vendor
Zyxel Networks
Product
GS1900-24E Firmware
Classifications
CWE-121, T1210
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 16, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 16, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=<= 2.90(AAHK.1)C0

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Zyxel Networks · GS1900-24E Firmwareversion=<= 2.90(AAHK.1)C0
Zyxel Networks · GS1900-10HP Firmwareversion=<= 2.90(AAZI.1)C0
Zyxel Networks · GS1900-8 Firmwareversion=<= 2.90(AAHH.1)C0
Zyxel Networks · GS1900-24 Firmwareversion=<= 2.90(AAHL.1)C0
Zyxel Networks · GS1900-48HPv2 Firmwareversion=<= 2.90(ABTQ.1)C0
Zyxel Networks · GS1900-8HP Firmwareversion=<= 2.90(AAHI.1)C0
Zyxel Networks · GS1900-24EP Firmwareversion=<= 2.90(ABTO.1)C0
Zyxel Networks · GS1900-24HPv2 Firmwareversion=<= 2.90(ABTP.1)C0
Zyxel Networks · GS1900-16 Firmwareversion=<= 2.90(AAHJ.1)C0
Zyxel Networks · GS1900-48 Firmwareversion=<= 2.90(AAHN.1)C0

Published CVSS scores

8.8Zyxel CorporationCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-121Stack-based Buffer Overflow
T1210Exploitation of Remote Services

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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