| Title | Tenda i3 V1.0.0.6(2204) Authentication Bypass Issues |
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| Description | A critical authentication bypass vulnerability exists in the i3 V1.0.0.6(2204) firmware.
The vulnerability is located in the `R7WebsSecurityHandler` function, which acts as the security filter for HTTP requests.
The application defines a whitelist of URL prefixes (e.g., `/public/`, `/lang/`) that are allowed to be accessed without authentication. The function uses `strncmp` to check if the request URL begins with these trusted prefixes: e.g., `if ( !strncmp(s1, "/public/", 8u) ... return 0;`.
However, the application fails to validate or canonicalize the subsequent part of the URL.
An unauthenticated remote attacker can send a crafted HTTP request that starts with a whitelisted prefix but employs directory traversal sequences (`../`) to escape the restricted directory. For example, a request to `/lang/../system_upgrade.asp` will satisfy the `strncmp` check (bypassing authentication) but will be resolved by the web server to the sensitive `system_upgrade.asp` page, granting full administrative access.
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| Source | ⚠️ https://github.com/MrXiaoFan/TendaVul/tree/main/tenda-i3-V1.0.0.6(2204)-R7WebsSecurityHandler-Authentication%20Bypass%20Issues |
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| User | Fan95 (UID 95969) |
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| Submission | 03/26/2026 10:04 (16 days ago) |
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| Moderation | 04/08/2026 19:35 (13 days later) |
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| Status | Accepted |
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| VulDB entry | 356297 [Tenda i3 1.0.0.6(2204) HTTP R7WebsSecurityHandler path traversal] |
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| Points | 20 |
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