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
- 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
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Tenda | firmware | affected |
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| Tenda | firmware | affected |
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| Tenda | firmware | affected |
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| Tenda | firmware | affected |
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| Tenda | firmware | affected |
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Fixes
Solution
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Workaround
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References
History
Mon, 06 Jul 2026 19:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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 | |
| Title | Hidden backdoor authentication mechanism in multiple versions of Tenda firmware allows admin access to web management interface | |
| References |
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Projects
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MITRE
Status: PUBLISHED
Assigner: certcc
Published:
Updated: 2026-07-06T20:37:55.739Z
Reserved: 2026-06-05T18:12:15.445Z
Link: CVE-2026-11405
Vulnrichment
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NVD
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Redhat
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OpenCVE Enrichment
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Weaknesses
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