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Vulnerability record · CVE-2023-22913 · published 24 April 2023

CVE-2023-22913: Zyxel usg flex 100 firmware command injection vulnerability

Zyxel · Usg Flex 100 Firmware

A post-authentication command injection vulnerability in the “account_operator.cgi” CGI program of Zyxel USG FLEX series firmware versions 4.50 through 5.35, and VPN series firmware versions 4.30 through 5.35, which could allow a remote authenticated attacker to modify device configuration data, resulting in denial-of-service (DoS) conditions on an affected device.

8.1 CVSS 3.1 High EPSS 1.3% · top 30.2% CWE-77 · Command injection
8.1CVSS 3.1 base score
1.3%EPSS exploitation probability, 30 days
NoNot in CISA KEV
11Affected product versions listed by NVD
2References
17 Jun 2026Last modified by NVD

Description

A post-authentication command injection vulnerability in the “account_operator.cgi” CGI program of Zyxel USG FLEX series firmware versions 4.50 through 5.35, and VPN series firmware versions 4.30 through 5.35, which could allow a remote authenticated attacker to modify device configuration data, resulting in denial-of-service (DoS) conditions on an affected device.

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

Affected products

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

References

LinkTags
https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-multiple-vulnerabilities-of-fire Vendor Advisory
https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-multiple-vulnerabilities-of-fire Vendor Advisory

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Related vulnerabilities

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

9.8CVE-2023-33010Zyxel firewall ID processing buffer overflow allows unauthenticated RCEA classic buffer overflow (CWE-120) exists in the ID processing function of multiple Zyxel firewall firmware lines, including ATP, USG FLEX, USG20(W)…KEVEPSS 29%analysed9.8CVE-2023-33009Zyxel firewall notification function buffer overflowA buffer overflow in the notification function of multiple Zyxel firewall and VPN firmware lines (ATP, USG FLEX, USG20(W)-VPN, VPN, ZyWALL/USG) allow…KEVEPSS 28%analysed9.8CVE-2023-28771Zyxel firewall firmware OS command injection via crafted packetsZyxel ZyWALL/USG, VPN, USG FLEX and ATP series firmware mishandle error messages, allowing OS command injection. An unauthenticated remote attacker c…KEVEPSS 99%analysed9.8CVE-2022-30525Zyxel firewall CGI OS command injectionThe CGI program in multiple Zyxel firewall and VPN firmware lines fails to neutralize OS command syntax, allowing command injection. The flaw affects…KEVEPSS 100%analysed9.8CVE-2020-29583Zyxel USG and ATP firmware hard-coded admin credentialZyxel USG and ATP firmware version 4.60 ships an undocumented account (zyfwp) whose password is stored in cleartext in the firmware and cannot be cha…KEVEPSS 90%analysed9.8CVE-2022-0342Zyxel firewall CGI authentication bypass grants admin accessThe CGI program in multiple Zyxel firewall firmware lines (USG/ZyWALL, USG FLEX, ATP, VPN, NSG) fails to properly enforce authentication, allowing a …EPSS 95%analysed9.8CVE-2021-35029Zyxel usg1900 firmware improper authentication vulnerabilityAn authentication bypasss vulnerability in the web-based management interface of Zyxel USG/Zywall series firmware versions 4.35 through 4.64 and USG …EPSS 2.3%8.8CVE-2023-33012Zyxel usg 20w-vpn firmware os command injection vulnerabilityA command injection vulnerability in the configuration parser of the Zyxel ATP series firmware versions 5.10 through 5.36 Patch 2, USG FLEX series fi…EPSS 9.9%

Source: NIST National Vulnerability Database (record CVE-2023-22913), CISA KEV, FIRST EPSS (scores of 2026-10-17). This page is refreshed as NVD updates the record.