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Vulnerability record · CVE-2021-35031 · published 28 December 2021

CVE-2021-35031: Zyxel gs1900-8 firmware os command injection vulnerability

Zyxel · Gs1900 8 Firmware

A vulnerability in the TFTP client of Zyxel GS1900 series firmware, XGS1210 series firmware, and XGS1250 series firmware, which could allow an authenticated LAN user to execute arbitrary OS commands via the GUI of the vulnerable device.

8.0 CVSS 3.1 High EPSS 0.46% · top 62.4% CWE-78 · OS command injection
8.0CVSS 3.1 base score, v2 7.7
0.46%EPSS exploitation probability, 30 days
NoNot in CISA KEV
14Affected product versions listed by NVD
2References
17 Jun 2026Last modified by NVD

Description

A vulnerability in the TFTP client of Zyxel GS1900 series firmware, XGS1210 series firmware, and XGS1250 series firmware, which could allow an authenticated LAN user to execute arbitrary OS commands via the GUI of the vulnerable device.

CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

14 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://www.zyxel.com/support/Zyxel_security_advisory_for_OS_command_injection_vulnerabilities_of_switches.shtml PatchVendor Advisory
https://www.zyxel.com/support/Zyxel_security_advisory_for_OS_command_injection_vulnerabilities_of_switches.shtml PatchVendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

8.8CVE-2026-7273Zyxel gs1900-8 firmware stack-based buffer overflow vulnerabilityA 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-base…KEVEPSS 2.5%9.8CVE-2019-15800Zyxel gs1900-8 firmware os command injection vulnerabilityAn issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0. Due to lack of input validation in the cmd_sys_traceroute_exec()…EPSS 3.9%9.8CVE-2016-1329Samsung x14j firmware improper authentication vulnerabilityCisco NX-OS 6.0(2)U6(1) through 6.0(2)U6(5) on Nexus 3000 devices and 6.0(2)A6(1) through 6.0(2)A6(5) and 6.0(2)A7(1) on Nexus 3500 devices has hardc…EPSS 3.7%9.8CVE-2015-5989Zyxel gs1900-10hp firmware permissions and access controls vulnerabilityBelkin F9K1102 2 devices with firmware 2.10.17 rely on client-side JavaScript code for authorization, which allows remote attackers to obtain adminis…EPSS 2.8%9.8CVE-2015-5988Zyxel gs1900-10hp firmware vulnerabilityThe web management interface on Belkin F9K1102 2 devices with firmware 2.10.17 has a blank password, which allows remote attackers to obtain administ…EPSS 2.7%9.1CVE-2019-15803Zyxel gs1900-8 firmware improper authentication vulnerabilityAn issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0. Through an undocumented sequence of keypresses, undocumented fun…EPSS 1.3%8.8CVE-2019-15799Zyxel gs1900-8 firmware improper privilege management vulnerabilityAn issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0. User accounts created through the web interface of the device, w…EPSS 2.3%8.8CVE-2016-1302Samsung x14j firmware improper access control vulnerabilityCisco Application Policy Infrastructure Controller (APIC) devices with software before 1.0(3h) and 1.1 before 1.1(1j) and Nexus 9000 ACI Mode switche…EPSS 2.2%

Source: NIST National Vulnerability Database (record CVE-2021-35031), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.