Critical severity · published Jul 6, 2026
CVE-2026-11405
Hidden backdoor authentication mechanism in multiple versions of Tenda firmware allows admin access to web management interface
9.8
CVSS
0.8%
EPSS
No
On KEV
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
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.8% · higher than 55% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FI
firmware · Tenda
US_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 · source: vendor
In the news
VulnerabilityCritical
Hidden Tenda Router Backdoor Grants Admin Access, No Patch Available
CERT/CC warns an unpatched backdoor in several Tenda routers lets attackers bypass login and gain full admin access with a hidden password. CERT/CC published an alert documenting an undocumented authentication backdoor in multiple Tenda firmware versions, tracked as CVE-2026-11405. The flaw gives anyone who knows the right password full administrative access to the device’s web […]
Jul 7, 2026·Security Affairs
VulnerabilityHigh
CERT/CC Warns of Hidden Admin Backdoor in Tenda Router Firmware
Several versions of firmware released by Chinese network device manufacturer Tenda have been found to embed an undocumented authentication backdoor that enables administrative access to the devices' web management interfaces, the CERT Coordination Center (CERT/CC) warned Monday. "An attacker can exploit this vulnerability, tracked as CVE-2026-11405, to bypass the password verification process
Jul 7, 2026·The Hacker News