VendorsZyxelzldany version
Vulnerabilities

Zyxel Zld any version

Ranked by severity, then by exploit likelihood. Click a CVE ID for its full record.

20CVEs
CVE-2020-25014
A stack-based buffer overflow in fbwifi_continue.cgi on Zyxel UTM and VPN series of gateways running firmware version V4.30 through to V4.55 allows remote unauthenticated attackers to execute arbitrary code via a crafted http packet.
Published 2020-11-27 · Modified
9.8EPSS 0.044
CVE-2024-11667
A directory traversal vulnerability in the web management interface of Zyxel ATP series firmware versions V5.00 through V5.38, USG FLEX series firmware versions V5.00 through V5.38, USG FLEX 50(W) series firmware versions V5.10 through V5.38, and USG20(W)-VPN series firmware versions V5.10 through V5.38 could allow an attacker to download or upload files via a crafted URL.
Published 2024-11-27 · Analyzed
9.8KEVEPSS 0.029
CVE-2020-29299
Certain Zyxel products allow command injection by an admin via an input string to chg_exp_pwd during a password-change action. This affects VPN On-premise before ZLD V4.39 week38, VPN Orchestrator before SD-OS V10.03 week32, USG before ZLD V4.39 week38, USG FLEX before ZLD V4.55 week38, ATP before ZLD V4.55 week38, and NSG before 1.33 patch 4.
Published 2020-12-27 · Modified
9.0EPSS 0.024
CVE-2025-9133
A missing authorization vulnerability in Zyxel ATP series firmware versions from V4.32 through V5.40, USG FLEX series firmware versions from V4.50 through V5.40, USG FLEX 50(W) series firmware versions from V4.16 through V5.40, and USG20(W)-VPN series firmware versions from V4.16 through V5.40 could allow a semi-authenticated attacker—who has completed only the first stage of the two-factor authentication (2FA) process—to view and download the system configuration from an affected device.
Published 2025-10-21 · Analyzed
8.1EPSS 0.055
CVE-2024-42057
A command injection vulnerability in the IPSec VPN feature of Zyxel ATP series firmware versions from V4.32 through V5.38, USG FLEX series firmware versions from V4.50 through V5.38, USG FLEX 50(W) series firmware versions from V4.16 through V5.38, and USG20(W)-VPN series firmware versions from V4.16 through V5.38 could allow an unauthenticated attacker to execute some OS commands on an affected device by sending a crafted username to the vulnerable device. Note that this attack could be successful only if the device was configured in User-Based-PSK authentication mode and a valid user with a long username exceeding 28 characters exists.
Published 2024-09-03 · Analyzed
8.1EPSS 0.013
CVE-2023-4398
An integer overflow vulnerability in the source code of the QuickSec IPSec toolkit used in the VPN feature of the Zyxel ATP series firmware versions 4.32 through 5.37, USG FLEX series firmware versions 4.50 through 5.37, USG FLEX 50(W) series firmware versions 4.16 through 5.37, USG20(W)-VPN series firmware versions 4.16 through 5.37, and VPN series firmware versions 4.30 through 5.37, could allow an unauthenticated attacker to cause denial-of-service (DoS) conditions on an affected device by sending a crafted IKE packet.
Published 2023-11-28 · Modified
7.5EPSS 0.009
CVE-2024-42058
A null pointer dereference vulnerability in Zyxel ATP series firmware versions from V4.32 through V5.38, USG FLEX series firmware versions from V4.50 through V5.38, USG FLEX 50(W) series firmware versions from V5.20 through V5.38, and USG20(W)-VPN series firmware versions from V5.20 through V5.38 could allow an unauthenticated attacker to cause DoS conditions by sending crafted packets to a vulnerable device.
Published 2024-09-03 · Analyzed
7.5EPSS 0.006
CVE-2025-8078
A post-authentication command injection vulnerability in Zyxel ATP series firmware versions from V4.32 through V5.40, USG FLEX series firmware versions from V4.50 through V5.40, USG FLEX 50(W) series firmware versions from V4.16 through V5.40, and USG20(W)-VPN series firmware versions from V4.16 through V5.40 could allow an authenticated attacker with administrator privileges to execute operating system (OS) commands on the affected device by passing a crafted string as an argument to a CLI command.
Published 2025-10-21 · Analyzed
7.2EPSS 0.014
CVE-2024-42059
A post-authentication command injection vulnerability in Zyxel ATP series firmware versions from V5.00 through V5.38, USG FLEX series firmware versions from V5.00 through V5.38, USG FLEX 50(W) series firmware versions from V5.00 through V5.38, and USG20(W)-VPN series firmware versions from V5.00 through V5.38 could allow an authenticated attacker with administrator privileges to execute some OS commands on an affected device by uploading a crafted compressed language file via FTP.
Published 2024-09-03 · Analyzed
7.2EPSS 0.013
CVE-2024-42060
A post-authentication command injection vulnerability in Zyxel ATP series firmware versions from V4.32 through V5.38, USG FLEX series firmware versions from V4.50 through V5.38, USG FLEX 50(W) series firmware versions from V4.16 through V5.38, and USG20(W)-VPN series firmware versions from V4.16 through V5.38 could allow an authenticated attacker with administrator privileges to execute some OS commands on an affected device by uploading a crafted internal user agreement file to the vulnerable device.
Published 2024-09-03 · Analyzed
7.2EPSS 0.013
CVE-2024-7203
A post-authentication command injection vulnerability in Zyxel ATP series firmware versions from V4.60 through V5.38 and USG FLEX series firmware versions from V4.60 through V5.38 could allow an authenticated attacker with administrator privileges to execute some operating system (OS) commands on an affected device by executing a crafted CLI command.
Published 2024-09-03 · Analyzed
7.2EPSS 0.013
CVE-2023-35139
A cross-site scripting (XSS) vulnerability in the CGI program of the Zyxel ATP series firmware versions 5.10 through 5.37, USG FLEX series firmware versions 5.00 through 5.37, USG FLEX 50(W) series firmware versions 5.10 through 5.37, USG20(W)-VPN series firmware versions 5.10 through 5.37, and VPN series firmware versions 5.00 through 5.37, could allow an unauthenticated LAN-based attacker to store malicious scripts in a vulnerable device. A successful XSS attack could then result in the stored malicious scripts being executed to steal cookies when the user visits the specific CGI used for dumping ZTP logs.
Published 2023-11-28 · Modified
6.1EPSS 0.005
CVE-2024-42061
A reflected cross-site scripting (XSS) vulnerability in the CGI program "dynamic_script.cgi" of Zyxel ATP series firmware versions from V4.32 through V5.38, USG FLEX series firmware versions from V4.50 through V5.38, USG FLEX 50(W) series firmware versions from V4.16 through V5.38, and USG20(W)-VPN series firmware versions from V4.16 through V5.38 could allow an attacker to trick a user into visiting a crafted URL with the XSS payload. The attacker could obtain browser-based information if the malicious script is executed on the victim’s browser.
Published 2024-09-03 · Analyzed
6.1EPSS 0.003
CVE-2023-35136
An improper input validation vulnerability in the “Quagga” package of the Zyxel ATP series firmware versions 4.32 through 5.37, USG FLEX series firmware versions 4.50 through 5.37, USG FLEX 50(W) series firmware versions 4.16 through 5.37, USG20(W)-VPN series firmware versions 4.16 through 5.37, and VPN series firmware versions 4.30 through 5.37, could allow an authenticated local attacker to access configuration files on an affected device.
Published 2023-11-28 · Modified
5.5EPSS 0.002
CVE-2023-37926
A buffer overflow vulnerability in the Zyxel ATP series firmware versions 4.32 through 5.37, USG FLEX series firmware versions 4.50 through 5.37, USG FLEX 50(W) series firmware versions 4.16 through 5.37, USG20(W)-VPN series firmware versions 4.16 through 5.37, and VPN series firmware versions 4.30 through 5.37, could allow an authenticated local attacker to cause denial-of-service (DoS) conditions by executing the CLI command to dump system logs on an affected device.
Published 2023-11-28 · Modified
5.5EPSS 0.002
CVE-2023-5960
An improper privilege management vulnerability in the hotspot feature of the Zyxel USG FLEX series firmware versions 4.50 through 5.37 and VPN series firmware versions 4.30 through 5.37 could allow an authenticated local attacker to access the system files on an affected device.
Published 2023-11-28 · Modified
5.5EPSS 0.002
CVE-2023-37925
An improper privilege management vulnerability in the debug CLI command of the Zyxel ATP series firmware versions 4.32 through 5.37, USG FLEX series firmware versions 4.50 through 5.37, USG FLEX 50(W) series firmware versions 4.16 through 5.37, USG20(W)-VPN series firmware versions 4.16 through 5.37, VPN series firmware versions 4.30 through 5.37, NWA50AX firmware version 6.29(ABYW.2), WAC500 firmware version 6.65(ABVS.1), WAX300H firmware version 6.60(ACHF.1), and WBE660S firmware version 6.65(ACGG.1), could allow an authenticated local attacker to access system files on an affected device.
Published 2023-11-28 · Modified
5.5EPSS 0.002
CVE-2023-5650
An improper privilege management vulnerability in the ZySH of the Zyxel ATP series firmware versions 4.32 through 5.37, USG FLEX series firmware versions 4.50 through 5.37, USG FLEX 50(W) series firmware versions 4.16 through 5.37, USG20(W)-VPN series firmware versions 4.16 through 5.37, and VPN series firmware versions 4.30 through 5.37, could allow an authenticated local attacker to modify the URL of the registration page in the web GUI of an affected device.
Published 2023-11-28 · Modified
5.5EPSS 0.002
CVE-2023-5797
An improper privilege management vulnerability in the debug CLI command of the Zyxel ATP series firmware versions 4.32 through 5.37, USG FLEX series firmware versions 4.50 through 5.37, USG FLEX 50(W) series firmware versions 4.16 through 5.37, USG20(W)-VPN series firmware versions 4.16 through 5.37, VPN series firmware versions 4.30 through 5.37, NWA50AX firmware version 6.29(ABYW.2), WAC500 firmware version 6.65(ABVS.1), WAX300H firmware version 6.60(ACHF.1), and WBE660S firmware version 6.65(ACGG.1), could allow an authenticated local attacker to access the administrator’s logs on an affected device.
Published 2023-11-28 · Modified
5.5EPSS 0.002
CVE-2024-6343
A buffer overflow vulnerability in the CGI program of Zyxel ATP series firmware versions from V4.32 through V5.38, USG FLEX series firmware versions from V4.50 through V5.38, USG FLEX 50(W) series firmware versions from V4.16 through V5.38, and USG20(W)-VPN series firmware versions from V4.16 through V5.38 could allow an authenticated attacker with administrator privileges to cause denial of service (DoS) conditions by sending a crafted HTTP request to a vulnerable device.
Published 2024-09-03 · Analyzed
4.9EPSS 0.006