CVE-2026-11405

Critical

Description

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

SeverityCritical
CVSS9.8
Exploit probability—
ProductTenda Firmware
PublishedJul 6, 2026
First seenJul 6, 2026
Weakness typeCWE-912CWE-912

How to fix

Sources list no fixed version or patch link for this vulnerability.

Affected products

ProductAffected versionsFixed in
Tenda firmwareUS_AC6V2.0RTL_V15.03.06.51_multi_T, US_AC5V1.0RTL_V15.03.06.48_multi_TDE01, US_AC10V1.0re_V15.03.06.46_multi_TDE01, US_W15EV1.0br_V15.11.0.5(1068_1567_841)_EN_TDE, US_FH1201V1.0BR_V1.2.0.14(408)_EN_TD—

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