Can you explain this vulnerability to me?

CVE-2026-7036 is a vulnerability in the Tenda i9 router firmware version 1.0.0.5(2204) affecting the HTTP Handler component, specifically the R7WebsSecurityHandler function.

This function is supposed to restrict unauthenticated access to certain URLs by checking if the URL starts with whitelisted prefixes like "/public/" or "/lang/". However, it fails to properly validate the rest of the URL after the prefix check.

An attacker can exploit this by crafting a URL that starts with a whitelisted prefix but includes directory traversal sequences ("../") to escape the restricted directory and access sensitive administrative pages without authentication.

For example, a request to "/public/../system_upgrade.asp" bypasses the whitelist check and grants direct access to the administrative interface, which normally requires login.

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How can this vulnerability impact me? :

This vulnerability allows a remote attacker to bypass authentication and gain unauthorized access to sensitive administrative pages on the Tenda i9 router.

Such unauthorized access can lead to unauthorized configuration changes, firmware upgrades, or other administrative actions that compromise the security and integrity of the device.

Because the exploit is publicly available, attackers can easily leverage this vulnerability to take control of affected devices remotely without any user interaction.

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How can this vulnerability be detected on my network or system? Can you suggest some commands?

This vulnerability can be detected by sending crafted HTTP GET requests to the Tenda i9 router that exploit the path traversal flaw in the R7WebsSecurityHandler function. Specifically, you can test if the router improperly allows access to administrative pages by using directory traversal sequences after a whitelisted URL prefix.

• Send an HTTP GET request to a URL like "/public/../system_upgrade.asp" and check if you receive the administrative page without authentication.
• Use tools like curl or wget to perform this test, for example: curl -i http://<router-ip>/public/../system_upgrade.asp
• If the response returns the administrative page content instead of a redirect to a login page (HTTP 302), the vulnerability is present.

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How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:

This vulnerability allows unauthenticated remote attackers to bypass authentication and gain direct access to administrative interfaces and sensitive resources on the Tenda i9 router. Such unauthorized access to sensitive data or administrative controls can lead to data breaches or unauthorized system changes.

As a result, this vulnerability could negatively impact compliance with common standards and regulations such as GDPR and HIPAA, which require protection of sensitive data and strict access controls to prevent unauthorized access.

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What immediate steps should I take to mitigate this vulnerability?

To mitigate the CVE-2026-7036 vulnerability in the Tenda i9 router firmware version V1.0.0.5(2204), immediate steps include restricting or disabling remote access to the HTTP administrative interface to prevent unauthenticated exploitation.

Additionally, monitor network traffic for suspicious requests that include directory traversal sequences such as '/../' in URLs targeting the router's web interface.

If possible, apply any available firmware updates or patches from the vendor that address this path traversal and authentication bypass issue.

As a temporary workaround, consider implementing network-level controls such as firewall rules to block unauthorized access to the router's HTTP service.

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