Vulnerability in Tenda Firmware
CVE-2026-11405
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
EPSS: 0.016 (74.1th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
Affected products
- Tenda Firmware — versions 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
Public proof-of-concept exploits
References
Frequently asked questions
- What is CVE-2026-11405?
- CVE-2026-11405 is a critical-severity vulnerability in Tenda Firmware, classified under CWE-912: HIDDEN FUNCTIONALITY. CVSS score: 9.8/10. Published 2026-07-06.
- How severe is CVE-2026-11405?
- Critical severity. CVSS v3 base score is 9.8 out of 10.
- Is CVE-2026-11405 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.