CVE-2025-14126: TOZED ZLT M30S Auth Bypass Vulnerability

CVE-2025-14126 Overview

CVE-2025-14126 is a hard-coded credentials vulnerability [CWE-259] affecting the web interface of TOZED ZLT M30S and ZLT M30S PRO routers running firmware versions 1.47 and 3.09.06. An attacker on the adjacent network can authenticate to the device using embedded credentials that cannot be removed or changed by the operator. The flaw has been publicly disclosed, and the vendor did not respond to coordinated disclosure attempts. Successful exploitation yields administrative access to the router, exposing confidentiality, integrity, and availability of the device and the traffic it routes.

Critical Impact

An adjacent attacker can log in to the router web interface using built-in credentials, taking full administrative control of the device and any traffic transiting it.

Affected Products

• TOZED ZLT M30S firmware 1.47
• TOZED ZLT M30S PRO firmware 3.09.06
• Web Interface component on both models

Discovery Timeline

• 2025-12-06 - CVE-2025-14126 published to NVD
• 2026-04-29 - Last updated in NVD database

Technical Details for CVE-2025-14126

Vulnerability Analysis

The vulnerability resides in an unspecified function of the web interface on TOZED ZLT M30S and ZLT M30S PRO routers. The firmware ships with hard-coded credentials that grant access to the management interface. Because the credentials are embedded in the firmware image, administrators cannot rotate or disable them through the standard configuration workflow.

An attacker who reaches the device over the local network can submit these credentials to the login endpoint and receive a valid administrative session. From that session, the attacker can change Wi-Fi settings, modify DNS resolvers, pivot to attached clients, or persist on the device. The exploit has been publicly disclosed, and the vendor has not responded to disclosure outreach.

Root Cause

The root cause is the inclusion of static authentication material inside the shipped firmware [CWE-259: Use of Hard-coded Credentials]. The credentials are identical across deployed units of the affected firmware versions, so disclosure of a single device's credentials compromises every device running the same build. There is no documented mechanism in the affected firmware to revoke or rotate the embedded credentials.

Attack Vector

Exploitation requires network adjacency, meaning the attacker must reach the router from the same Layer 2 segment, an associated Wi-Fi SSID, or a routed local network with reachability to the management interface. No prior authentication and no user interaction are required. Once the attacker submits the known credentials to the web interface login handler, they obtain administrative privileges and can issue arbitrary configuration changes through the standard management UI and any backing APIs.

No verified proof-of-concept code is published in the referenced advisories. Technical details of the credential string and login flow are described in the VulDB entry #334521.

Detection Methods for CVE-2025-14126

Indicators of Compromise

• Successful web interface logins from unexpected adjacent hosts, particularly outside normal administrative source addresses.
• Configuration changes on the router, such as modified DNS servers, altered firewall rules, or new port forwards, that were not initiated by an authorized administrator.
• New or modified administrative accounts and persistence artifacts in router logs.
• Outbound traffic from the router to unfamiliar command-and-control or DNS endpoints.

Detection Strategies

• Inspect router authentication logs for logins occurring outside business hours or from clients that have never previously administered the device.
• Compare current router configuration against a known-good baseline and alert on unauthorized deltas, especially in DNS, DHCP, and routing tables.
• Monitor adjacent network traffic for HTTP or HTTPS POST requests to the router's login endpoint from unmanaged hosts.

Monitoring Recommendations

• Forward router syslog and authentication events to a central log platform for retention and correlation.
• Place the device management VLAN behind network access control and alert on any new MAC address that reaches the management interface.
• Periodically scan firmware versions across the fleet to identify units still running 1.47 or 3.09.06.

How to Mitigate CVE-2025-14126

Immediate Actions Required

• Restrict access to the router web interface to a dedicated management VLAN or specific administrative IPs, blocking it from general LAN and Wi-Fi client segments.
• Disable remote management features and any WAN-side access to the administrative interface.
• Audit the device for unauthorized configuration changes, new accounts, and altered DNS settings, then restore known-good configuration where needed.
• Treat affected devices as untrusted on networks handling sensitive traffic until they can be replaced or isolated.

Patch Information

No vendor patch is currently available. The vendor was contacted prior to public disclosure but did not respond. Operators should track the VulDB advisory for updates and consider replacing the affected models with hardware from vendors that support credential rotation and coordinated disclosure.

Workarounds

• Segment the affected routers onto an isolated VLAN and apply Layer 3 access control lists that permit only authorized management hosts to reach the web interface.
• Place the router behind an upstream firewall and block lateral access from client subnets to the device management port.
• Replace affected units with hardware that does not rely on hard-coded credentials when handling sensitive network segments.

# Example: restrict management access using an upstream firewall (iptables)
# Replace 192.0.2.10 with your authorized admin host and 10.0.0.1 with the router IP
iptables -A FORWARD -s 192.0.2.10 -d 10.0.0.1 -p tcp --dport 80 -j ACCEPT
iptables -A FORWARD -s 192.0.2.10 -d 10.0.0.1 -p tcp --dport 443 -j ACCEPT
iptables -A FORWARD -d 10.0.0.1 -p tcp --dport 80 -j DROP
iptables -A FORWARD -d 10.0.0.1 -p tcp --dport 443 -j DROP