CVE-2026-11405 (GCVE-0-2026-11405)

Vulnerability from cvelistv5 – Published: 2026-07-06 19:17 – Updated: 2026-07-08 13:40
VLAI
Title
Hidden backdoor authentication mechanism in multiple versions of Tenda firmware allows admin access to web management interface
Summary
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
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
SSVC
Exploitation: none Automatable: yes Technical Impact: total
CISA Coordinator (v2.0.3)
CWE
Assigner
References
Impacted products
Vendor Product Version
Tenda firmware Affected: US_AC6V2.0RTL_V15.03.06.51_multi_T
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Tenda firmware Affected: US_AC5V1.0RTL_V15.03.06.48_multi_TDE01
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Tenda firmware Affected: US_AC10V1.0re_V15.03.06.46_multi_TDE01
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Tenda firmware Affected: US_W15EV1.0br_V15.11.0.5(1068_1567_841)_EN_TDE
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Tenda firmware Affected: US_FH1201V1.0BR_V1.2.0.14(408)_EN_TD
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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.