CVE-2026-11405 PUBLISHED

Hidden backdoor authentication mechanism in multiple versions of Tenda firmware allows admin access to web management interface

Assigner: certcc
Reserved: 05.06.2026 Published: 06.07.2026 Updated: 06.07.2026

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

Product Status

Vendor Tenda
Product firmware
Versions
  • Version US_AC6V2.0RTL_V15.03.06.51_multi_T is affected
Vendor Tenda
Product firmware
Versions
  • Version US_AC5V1.0RTL_V15.03.06.48_multi_TDE01 is affected
Vendor Tenda
Product firmware
Versions
  • Version US_AC10V1.0re_V15.03.06.46_multi_TDE01 is affected
Vendor Tenda
Product firmware
Versions
  • Version US_W15EV1.0br_V15.11.0.5(1068_1567_841)_EN_TDE is affected
Vendor Tenda
Product firmware
Versions
  • Version US_FH1201V1.0BR_V1.2.0.14(408)_EN_TD is affected

References

Problem Types

  • CWE-912: Hidden Functionality