CVE-2026-7273 - Vulnerability Details

- CGI Buffer Overflow in Zyxel GS1900 Switches Enables Remote Command Execution

Description

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: 2026-06-16

Score: 8.8 High

EPSS: 1.3% Low

KEV: Yes

Impact:

Action:

Analysis

Impact

The vulnerability is a stack‑based buffer overflow in the CGI program of Zyxel GS1900 switches. An attacker on the same local network can exploit this flaw by sending a crafted HTTP request, potentially causing the switch to execute operating‑system commands. This could lead to full control over the device’s operating system.

Affected Systems

Affected devices include Zyxel GS1900‑8, GS1900‑8HP, GS1900‑10HP, GS1900‑16, GS1900‑24, GS1900‑24E, GS1900‑24EP, GS1900‑24HPv2, GS1900‑48, and GS1900‑48HPv2 firmware versions up through and including 2.90(ABTQ.1)C0.

Risk and Exploitability

The CVSS score of 8.8 indicates high severity, while the EPSS score of 1% suggests a low probability of exploitation at present. It is listed in CISA’s KEV catalog. Exploitation requires an unauthenticated connection from a device on the same local network that can reach the switch’s HTTP management interface, after which the attacker could run arbitrary OS commands on the device.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Zyxel

GS1900-48HPv2 firmware

unaffected

Version	Status	Constraints
`<= 2.90(ABTQ.1)C0`	affected	—

Zyxel

GS1900-8 firmware

unaffected

Version	Status	Constraints
`<= 2.90(AAHH.1)C0`	affected	—

Zyxel

GS1900-8HP firmware

unaffected

Version	Status	Constraints
`<= 2.90(AAHI.1)C0`	affected	—

Zyxel

GS1900-10HP firmware

unaffected

Version	Status	Constraints
`<= 2.90(AAZI.1)C0`	affected	—

Zyxel

GS1900-16 firmware

unaffected

Version	Status	Constraints
`<= 2.90(AAHJ.1)C0`	affected	—

Zyxel

GS1900-24 firmware

unaffected

Version	Status	Constraints
`<= 2.90(AAHL.1)C0`	affected	—

Zyxel

GS1900-24E firmware

unaffected

Version	Status	Constraints
`<= 2.90(AAHK.1)C0`	affected	—

Zyxel

GS1900-24EP firmware

unaffected

Version	Status	Constraints
`<= 2.90(ABTO.1)C0`	affected	—

Zyxel

GS1900-24HPv2 firmware

unaffected

Version	Status	Constraints
`<= 2.90(ABTP.1)C0`	affected	—

Zyxel

GS1900-48 firmware

unaffected

Version	Status	Constraints
`<= 2.90(AAHN.1)C0`	affected	—

Configuration 1 [-]

AND

cpe:2.3:o:zyxel:gs1900-8_firmware:*:*:*:*:*:*:*:*

cpe:2.3:h:zyxel:gs1900-8:-:*:*:*:*:*:*:*

Configuration 2 [-]

AND

cpe:2.3:o:zyxel:gs1900-8hp_firmware:*:*:*:*:*:*:*:*

cpe:2.3:h:zyxel:gs1900-8hp:-:*:*:*:*:*:*:*

Configuration 3 [-]

AND

cpe:2.3:o:zyxel:gs1900-10hp_firmware:*:*:*:*:*:*:*:*

cpe:2.3:h:zyxel:gs1900-10hp:-:*:*:*:*:*:*:*

Configuration 4 [-]

AND

cpe:2.3:o:zyxel:gs1900-16_firmware:*:*:*:*:*:*:*:*

cpe:2.3:h:zyxel:gs1900-16:-:*:*:*:*:*:*:*

Configuration 5 [-]

AND

cpe:2.3:o:zyxel:gs1900-24_firmware:*:*:*:*:*:*:*:*

cpe:2.3:h:zyxel:gs1900-24:-:*:*:*:*:*:*:*

Configuration 6 [-]

AND

cpe:2.3:o:zyxel:gs1900-24e_firmware:*:*:*:*:*:*:*:*

cpe:2.3:h:zyxel:gs1900-24e:-:*:*:*:*:*:*:*

Configuration 7 [-]

AND

cpe:2.3:o:zyxel:gs1900-24ep_firmware:*:*:*:*:*:*:*:*

cpe:2.3:h:zyxel:gs1900-24ep:-:*:*:*:*:*:*:*

Configuration 8 [-]

AND

cpe:2.3:o:zyxel:gs1900-24hpv2_firmware:*:*:*:*:*:*:*:*

cpe:2.3:h:zyxel:gs1900-24hpv2:-:*:*:*:*:*:*:*

Configuration 9 [-]

AND

cpe:2.3:o:zyxel:gs1900-48_firmware:*:*:*:*:*:*:*:*

cpe:2.3:h:zyxel:gs1900-48:-:*:*:*:*:*:*:*

Configuration 10 [-]

AND

cpe:2.3:o:zyxel:gs1900-48hpv2_firmware:*:*:*:*:*:*:*:*

cpe:2.3:h:zyxel:gs1900-48hpv2:-:*:*:*:*:*:*:*

No data.

Vendor Product Confidence Versions

Zyxel

Gs1900-10hp Firmware

100%

Version	Status	Scheme	Platform
`[0,2.90(AAZI.1)C0]`	affected	generic	—

Zyxel

Gs1900-16 Firmware

100%

Version	Status	Scheme	Platform
`[0,2.90(AAHJ.1)C0]`	affected	generic	—

Zyxel

Gs1900-24 Firmware

100%

Version	Status	Scheme	Platform
`[0,2.90(AAHL.1)C0]`	affected	generic	—

Zyxel

Gs1900-24e Firmware

100%

Version	Status	Scheme	Platform
`[0,2.90(AAHK.1)C0]`	affected	generic	—

Zyxel

Gs1900-24ep Firmware

100%

Version	Status	Scheme	Platform
`[0,2.90(ABTO.1)C0]`	affected	generic	—

Zyxel

Gs1900-24hpv2 Firmware

100%

Version	Status	Scheme	Platform
`[0,2.90(ABTP.1)C0]`	affected	generic	—

Zyxel

Gs1900-48 Firmware

100%

Version	Status	Scheme	Platform
`[0,2.90(AAHN.1)C0]`	affected	generic	—

Zyxel

Gs1900-48hpv2 Firmware

100%

Version	Status	Scheme	Platform
`[0,2.90(ABTQ.1)C0]`	affected	generic	—

Zyxel

Gs1900-8 Firmware

100%

Version	Status	Scheme	Platform
`[0,2.90(AAHH.1)C0]`	affected	generic	—

Zyxel

Gs1900-8hp Firmware

100%

Version	Status	Scheme	Platform
`[0,2.90(AAHI.1)C0]`	affected	generic	—

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Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

Upgrade Zyxel GS1900 firmware to a version newer than 2.90(ABTQ.1)C0 that resolves the buffer overflow.
Restrict or disable CGI access on the switch to limit exposure to HTTP requests.
Segment the network so that unauthenticated LAN devices cannot reach the switch’s HTTP management interface.

Generated by OpenCVE AI on September 25, 2026 at 01:24 UTC.

Tracking

Sign in to view the affected projects.

Advisories

No advisories yet.

No CVSS v4.0

Attack Vector Adjacent Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is in the KEV database since Sept. 21, 2026.

The EPSS score is 0.01286.

Exploitation active

Automatable no

Technical Impact total

References

Link	Providers
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-7273
https://www.greynoise.io/blog/open-season-on-kapibala-attacker-steals-government-records-wordpress-exploitation
https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-stack-based-buffer-overflow-vulnerability-in-gs1900-series-switches-06-16-2026

History

Fri, 25 Sep 2026 01:45:00 +0000

Type	Values Removed	Values Added
Title		CGI Buffer Overflow in Zyxel GS1900 Switches Enables Remote Command Execution

Tue, 22 Sep 2026 16:30:00 +0000

Type	Values Removed	Values Added
Title	Zyxel GS1900 Switches Buffer Overflow Enables LAN Attacker to Execute OS Commands

Tue, 22 Sep 2026 12:30:00 +0000

Type	Values Removed	Values Added
First Time appeared		Zyxel gs1900-10hp Zyxel gs1900-16 Zyxel gs1900-24 Zyxel gs1900-24e Zyxel gs1900-24ep Zyxel gs1900-24hpv2 Zyxel gs1900-48 Zyxel gs1900-48hpv2 Zyxel gs1900-8 Zyxel gs1900-8hp
CPEs		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:-:::::::* cpe:2.3:h:zyxel:gs1900-8:-:::::::* cpe:2.3:h:zyxel:gs1900-8hp:-:::::::* cpe:2.3:o:zyxel:gs1900-10hp_firmware:::::::: cpe:2.3:o:zyxel:gs1900-16_firmware:::::::: cpe:2.3:o:zyxel:gs1900-24_firmware:::::::: cpe:2.3:o:zyxel:gs1900-24e_firmware:::::::: cpe:2.3:o:zyxel:gs1900-24ep_firmware:::::::: cpe:2.3:o:zyxel:gs1900-24hpv2_firmware:::::::: cpe:2.3:o:zyxel:gs1900-48_firmware:::::::: cpe:2.3:o:zyxel:gs1900-48hpv2_firmware:::::::: cpe:2.3:o:zyxel:gs1900-8_firmware:::::::: cpe:2.3:o:zyxel:gs1900-8hp_firmware::::::::
Vendors & Products		Zyxel gs1900-10hp Zyxel gs1900-16 Zyxel gs1900-24 Zyxel gs1900-24e Zyxel gs1900-24ep Zyxel gs1900-24hpv2 Zyxel gs1900-48 Zyxel gs1900-48hpv2 Zyxel gs1900-8 Zyxel gs1900-8hp

Mon, 21 Sep 2026 20:45:00 +0000

Type	Values Removed	Values Added
Title		Zyxel GS1900 Switches Buffer Overflow Enables LAN Attacker to Execute OS Commands

Mon, 21 Sep 2026 20:30:00 +0000

Type	Values Removed	Values Added
References		https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-7273 https://www.greynoise.io/blog/open-season-on-kapibala-attacker-steals-government-records-wordpress-exploitation
Metrics	ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}`	ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'active', 'Technical Impact': 'total'}, 'version': '2.0.3'}`

Mon, 21 Sep 2026 19:45:00 +0000

Type	Values Removed	Values Added
Metrics		kev `{'dateAdded': '2026-09-21T00:00:00+00:00', 'dueDate': '2026-09-24T00:00:00+00:00'}`

Thu, 18 Jun 2026 04:45:00 +0000

Type	Values Removed	Values Added
Title	Stack-Based Buffer Overflow in Zyxel GS1900 Switch Firmware

Tue, 16 Jun 2026 21:15:00 +0000

Type	Values Removed	Values Added
Title		Stack-Based Buffer Overflow in Zyxel GS1900 Switch Firmware

Tue, 16 Jun 2026 13:30:00 +0000

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}`

Tue, 16 Jun 2026 08:45:00 +0000

Type	Values Removed	Values Added
First Time appeared		Zyxel Zyxel gs1900-10hp Firmware Zyxel gs1900-16 Firmware Zyxel gs1900-24 Firmware Zyxel gs1900-24e Firmware Zyxel gs1900-24ep Firmware Zyxel gs1900-24hpv2 Firmware Zyxel gs1900-48 Firmware Zyxel gs1900-48hpv2 Firmware Zyxel gs1900-8 Firmware Zyxel gs1900-8hp Firmware
Vendors & Products		Zyxel Zyxel gs1900-10hp Firmware Zyxel gs1900-16 Firmware Zyxel gs1900-24 Firmware Zyxel gs1900-24e Firmware Zyxel gs1900-24ep Firmware Zyxel gs1900-24hpv2 Firmware Zyxel gs1900-48 Firmware Zyxel gs1900-48hpv2 Firmware Zyxel gs1900-8 Firmware Zyxel gs1900-8hp Firmware

Tue, 16 Jun 2026 06:30:00 +0000

Type	Values Removed	Values Added
Description		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.
Weaknesses		CWE-121
References		https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-stack-based-buffer-overflow-vulnerability-in-gs1900-series-switches-06-16-2026
Metrics		cvssV3_1 `{'score': 8.8, 'vector': 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}`

Subscriptions

Zyxel Gs1900-10hp Gs1900-10hp Firmware Gs1900-16 Gs1900-16 Firmware Gs1900-24 Gs1900-24 Firmware Gs1900-24e Gs1900-24e Firmware Gs1900-24ep Gs1900-24ep Firmware Gs1900-24hpv2 Gs1900-24hpv2 Firmware Gs1900-48 Gs1900-48 Firmware Gs1900-48hpv2 Gs1900-48hpv2 Firmware Gs1900-8 Gs1900-8 Firmware Gs1900-8hp Gs1900-8hp Firmware

MITRE

Status: PUBLISHED

Assigner: Zyxel

Published: 2026-06-16T02:20:29.847Z

Updated: 2026-09-22T03:55:39.207Z

Reserved: 2026-04-28T06:21:36.574Z

Link: CVE-2026-7273

Vulnrichment

Updated: 2026-06-16T12:38:21.874Z

NVD

Status : Analyzed

Published: 2026-06-16T03:16:13.557

Modified: 2026-09-22T12:10:51.067

Link: CVE-2026-7273

Redhat

No data.

OpenCVE Enrichment

Updated: 2026-09-25T01:30:20Z

Weaknesses

CWE-121
Stack-based Buffer Overflow

Impact

Affected Systems

Risk and Exploitability

Tracking

Attack Vector Adjacent Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

Exploitation active

Automatable no

Technical Impact total

Subscriptions

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