CVE-2026-11405 — Hidden backdoor authentication mechanism in multiple versions of Tenda firmware allows admin access to web management interface
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…
Published: 2026-07-06 · CVSS: 9.8 · CVSS 3.1
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
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7