Tenda Router Login /bin/httpd login Password backdoor

Summaryinfo

A vulnerability labeled as critical has been found in Tenda Router. This issue affects the function Login of the file /bin/httpd of the component Login Handler. The manipulation of the argument Password results in backdoor. This vulnerability is reported as CVE-2026-11405. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability was found in Tenda Router (the affected version unknown). It has been classified as critical. Affected is the function login of the file /bin/httpd of the component Login Handler. The manipulation of the argument password with an unknown input leads to a backdoor vulnerability. CWE is classifying the issue as CWE-912. The product contains functionality that is not documented, not part of the specification, and not accessible through an interface or command sequence that is obvious to the product's users or administrators. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

The web server binary /bin/httpd contains a hidden backdoor authentication mechanism in the login() function at 004c88b8. - The function contains a normal authentication path using MD5/hash-based password verification (prod_encode64/PasswordToMd5/check_rand_key). - After normal authentication fails, it calls GetValue("sys.rzadmin.password") to read a backdoor password from the device configuration. - It performs a direct strcmp() comparison (plaintext, not hashed) between the config value and the user-supplied password. A successful match grants role=2 (admin-level access) and creates a valid session. The rzadmin username is never checked — any username works with the backdoor

This vulnerability is traded as CVE-2026-11405 since 06/05/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 07/06/2026). The MITRE ATT&CK project declares the attack technique as T1588.001.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Type

• Router Operating System

Vendor

• Tenda

Name

• Router

License

• commercial

Website

• Vendor: https://www.tenda.com.cn/

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CPE 2.2info

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