Insufficiently Protected Credentials vulnerability in Zyxel Networks WAH7601 allows Retrieve Embedded Sensitive Data.

This issue affects WAH7601: through 20072026.

I published my technical write-up for CVE-2026-8508, a pre-authentication trust-boundary flaw in Zyxel's guest Wi-Fi social-login flow.

The analysis is based on the WAX650S, while Zyxel's advisory expanded the affected scope to 39 models (APs, FWA7 units, and a security router). The post includes root cause, affected versions, remediation, and the reproduction environment.

Technical analysis of CVE-2026-6837, an authenticated command-injection vulnerability in Zyxel’s PKCS#12 certificate export flow.

The post covers the vulnerable execution path, root cause, affected firmware scope, and the firmware-emulation methodology used during analysis.

I published my technical write-up for CVE-2026-6837, an authenticated command-injection issue in Zyxel’s certificate export functionality.

The analysis is based on the WAX650S, while Zyxel’s advisory expanded the affected scope to 18 AP models. The post includes root cause, affected versions, remediation, and the reproduction environment.

A post-authentication command injection vulnerability in the "export-cgi" CGI program in Zyxel WAX650S firmware versions through 7.10(ABRM.4)C0 could allow an authenticated attacker with administrator privileges to execute OS commands on an affected device.

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.

An improper authentication vulnerability in the "sociallogin.cgi" CGI program in Zyxel WAX650S firmware versions through 7.10(ABRM.4)C0 could allow an attacker on the WLAN to bypass captive portal authentication.

A path traversal vulnerability in the CLI command used to execute configuration files in Zyxel ATP series firmware versions from V4.32 through V5.42 Patch 1, USG FLEX series firmware versions from V4.50 through V5.42 Patch 1, USG FLEX 50(W) series firmware versions from V4.16 through V5.42 Patch 1, and USG20(W)-VPN series firmware versions from V4.16 through V5.42 Patch 1 could allow an authenticated attacker with administrator privileges to execute a crafted malicious configuration file on an affected device.

Zyxel EMG2926 routers contain a command injection vulnerability located in the diagnostic tools, specifically the nslookup function. A malicious user may exploit numerous vectors to execute malicious commands on the router, such as the pingip parameter to the expert/maintenance/diagnostic/nslookup URI.

A post-authentication command injection vulnerability in the EasyMesh-related APIs of Zyxel DX3300-T0 firmware versions through 5.50(ABVY.7.1)C0 could allow an authenticated, adjacent attacker with administrator privileges to execute OS commands on an affected device.

A post-authentication command injection vulnerability in the “DomainName” parameter of the DHCP configuration file in Zyxel DX3301-T0 and EX3301-T0 firmware versions through 5.50(ABVY.7.1)C0 could allow an authenticated attacker with administrator privileges to execute OS commands on an affected device.

A missing authorization vulnerability in Zyxel GS1200-5v3 firmware versions through 1.00(ACPS.2)C0, GS1200-8v3 firmware versions through 1.00(ACPT.2)C0,  GS1200-5HPv3 firmware versions through 1.00(ACPU.2)C0, GS1200-8HPv3 firmware versions through 1.00(ACPV.2)C0, and GS1200-10v3 firmware versions through 1.00(ACPW.2)C0 could allow a LAN-based, unauthenticated attacker to read the system configuration from a log file via a crafted HTTP request.

A buffer overflow vulnerability in the UPnP AddPortMapping() command in Zyxel VMG4005-B50B firmware versions through 5.13(ABRL.5.4)C0 could allow an adjacent attacker to trigger a temporary denial-of-service (DoS) condition affecting the UPnP function of the affected device.

A buffer overflow vulnerability in the UPnP DeletePortMapping() command in Zyxel VMG4005-B50B firmware versions through 5.13(ABRL.5.4)C0 could allow an adjacent attacker to trigger a temporary denial-of-service (DoS) condition affecting the UPnP function of the affected device.

UNSUPPORTED WHEN ASSIGNED An improper encoding or escaping vulnerability in the CGI program of Zyxel WRE6505 v2 firmware version V1.00(ABDV.3)C0 could allow an adjacent attacker on the WLAN to cause a denial-of-service (DoS) condition in the web management interface by convincing an authenticated administrator to visit the “AP Select” page while a malformed SSID is present.

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.

UNSUPPORTED WHEN ASSIGNED A buffer overflow vulnerability in the formWep(), formWlAc(), formPasswordSetup(), formUpgradeCert(), and formDelcert() functions of the “webs” binary in Zyxel NWA1100-N customized firmware version 1.00(AACE.1)C0 could allow an attacker to trigger a denial-of-service (DoS) condition by sending a crafted HTTP request to a vulnerable device.

UNSUPPORTED WHEN ASSIGNED A command injection vulnerability in the CGI program of Zyxel WRE6505 v2 firmware version V1.00(ABDV.3)C0 could allow an adjacent attacker on the LAN to execute operating system (OS) commands on a vulnerable device by sending a crafted HTTP request.

UNSUPPORTED WHEN ASSIGNED An improper restriction of excessive authentication attempts vulnerability in the web management interface of Zyxel WRE6505 v2 firmware version V1.00(ABDV.3)C0 could allow an adjacent attacker on the LAN to brute-force the password and bypass authentication.

UNSUPPORTED WHEN ASSIGNED An insecure storage of sensitive information vulnerability in the configuration file of Zyxel WRE6505 v2 firmware version V1.00(ABDV.3)C0 could allow a local attacker with administrator privileges to download and decrypt a backup configuration file.

A buffer overflow vulnerability in the URL parser of the zhttpd web server in Zyxel VMG8825-T50K firmware versions prior to V5.50(ABOM.5)C0 could allow an unauthenticated attacker to cause denial-of-service (DoS) conditions and potentially execute arbitrary code by sending a specially crafted HTTP request.

A path traversal vulnerability in the fileupload-cgi CGI program of Zyxel NWA50AX PRO firmware version 7.10(ACGE.2) and earlier could allow an authenticated attacker with administrator privileges to access specific directories and delete files, such as the configuration file, on the affected device.

UNSUPPORTED WHEN ASSIGNED A post-authentication command injection vulnerability in the management commands of the legacy DSL CPE Zyxel VMG4325-B10A firmware version 1.00(AAFR.4)C020170615 could allow an authenticated attacker to execute operating system (OS) commands on an affected device via Telnet.

UNSUPPORTED WHEN ASSIGNED A post-authentication command injection vulnerability in the CGI program of the legacy DSL CPE Zyxel VMG4325-B10A firmware version 1.00(AAFR.4)C020170615 could allow an authenticated attacker to execute operating system (OS) commands on an affected device by sending a crafted HTTP POST request.

A command injection vulnerability in the access point (AP) management feature of the Zyxel ATP series firmware versions 5.00 through 5.36 Patch 2, USG FLEX series firmware versions 5.00 through 5.36 Patch 2, USG FLEX 50(W) series firmware versions 5.00 through 5.36 Patch 2, USG20(W)-VPN series firmware versions 5.00 through 5.36 Patch 2, VPN series firmware versions 5.00 through 5.36 Patch 2, NXC2500 firmware versions 6.10(AAIG.0) through 6.10(AAIG.3), and NXC5500 firmware versions 6.10(AAOS.0) through 6.10(AAOS.4), could allow an unauthenticated, LAN-based attacker to execute some OS commands on an affected device if the attacker could trick an authorized administrator to add their IP address to the managed AP list in advance.

A command injection vulnerability in the Free Time WiFi hotspot feature of the Zyxel USG FLEX series firmware versions 4.50 through 5.36 Patch 2 and VPN series firmware versions 4.20 through 5.36 Patch 2, could allow an unauthenticated, LAN-based attacker to execute some OS commands on an affected device.

A buffer overflow vulnerability in the Zyxel ATP series firmware versions 4.32 through 5.36 Patch 2, USG FLEX series firmware versions 4.50 through 5.36 Patch 2, USG FLEX 50(W) series firmware versions 4.16 through 5.36 Patch 2, USG20(W)-VPN series firmware versions 4.16 through 5.36 Patch 2, VPN series firmware versions 4.30 through 5.36 Patch 2, NXC2500 firmware versions 6.10(AAIG.0) through 6.10(AAIG.3), and NXC5500 firmware versions 6.10(AAOS.0) through 6.10(AAOS.4), could allow an unauthenticated, LAN-based attacker to cause denial of service (DoS) conditions by sending a crafted request to the CAPWAP daemon.

A command injection vulnerability in the hotspot management feature of the Zyxel ATP series firmware versions 4.60 through 5.36 Patch 2, USG FLEX series firmware versions 4.60 through 5.36 Patch 2, USG FLEX 50(W) series firmware versions 4.60 through 5.36 Patch 2, USG20(W)-VPN series firmware versions 4.60 through 5.36 Patch 2, and VPN series firmware versions 4.60 through 5.36 Patch 2, could allow an unauthenticated, LAN-based attacker to execute some OS commands on an affected device if the attacker could trick an authorized administrator to add their IP address to the list of trusted RADIUS clients in advance.

A buffer overflow vulnerability in the ID processing function in Zyxel ATP series firmware versions 4.32 through 5.36 Patch 1, USG FLEX series firmware versions 4.50 through 5.36 Patch 1, USG FLEX 50(W) firmware versions 4.25 through 5.36 Patch 1, USG20(W)-VPN firmware versions 4.25 through 5.36 Patch 1, VPN series firmware versions 4.30 through 5.36 Patch 1, ZyWALL/USG series firmware versions 4.25 through 4.73 Patch 1, could allow an unauthenticated attacker to cause denial-of-service (DoS) conditions and even a remote code execution on an affected device.

A format string vulnerability in the Zyxel ATP series firmware versions 5.10 through 5.36 Patch 2, USG FLEX series firmware versions 5.00 through 5.36 Patch 2, USG FLEX 50(W) series firmware versions 5.10 through 5.36 Patch 2, USG20(W)-VPN series firmware versions 5.10 through 5.36 Patch 2, and VPN series firmware versions 5.00 through 5.36 Patch 2, could allow an unauthenticated, LAN-based attacker to execute some OS commands by using a crafted PPPoE configuration on an affected device when the cloud management mode is enabled.