Overview
Recently, a critical vulnerability labeled CVE-2025-29515 was identified within the firmware of the D-Link DSL-7740C. This vulnerability pertains to incorrect access control in the DELT_file.xgi endpoint, which could potentially allow attackers to modify arbitrary settings within the device’s XML database. This includes the ability to modify the administrator’s password, which could lead to a complete system compromise and data leakage.
This issue primarily affects users of the D-Link DSL-7740C with the specific firmware version DSL7740C.V6.TR069.20211230. Given the ubiquitous nature of D-Link products in both home and office environments, understanding and mitigating this vulnerability is of utmost importance to maintain system integrity and protect sensitive information.
Vulnerability Summary
CVE ID: CVE-2025-29515
Severity: Critical (9.8 CVSS)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Complete system compromise, potential data leakage
Affected Products
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Product | Affected Versions
D-Link DSL-7740C | DSL7740C.V6.TR069.20211230
How the Exploit Works
The vulnerability arises from insufficient access control on the DELT_file.xgi endpoint in the device’s firmware. This endpoint allows for modifications to the device’s XML database, which includes critical system settings and user credentials.
Attackers can exploit this vulnerability by sending specifically crafted HTTP requests to the endpoint. As there are no proper access controls, these requests are processed without verification, allowing for unauthorized changes to the system’s settings, including the modification of the administrator’s password.
Conceptual Example Code
Here’s a conceptual example of how an attacker might exploit this vulnerability. This example uses an HTTP POST request to modify the administrator’s password:
POST /DELT_file.xgi HTTP/1.1
Host: target.example.com
Content-Type: application/xml
<xml>
<admin>
<password>new_password</password>
</admin>
</xml>In this example, “new_password” would be the attacker’s chosen password. Once this request is processed by the vulnerable device, the administrator’s password would be changed, thus granting the attacker full access to the system and its data.