Wallos is an open-source, self-hostable personal subscription tracker. Versions 4.6.0 and below contain a Server-Side Request Forgery (SSRF) vulnerability in the subscription and payment logo/icon upload functionality. The application validates the IP address of the provided URL before making the request, but allows HTTP redirects (CURLOPT_FOLLOWLOCATION = true), enabling an attacker to bypass the IP validation and access internal resources, including cloud instance metadata endpoints. The getLogoFromUrl() function validates the URL by resolving the hostname and checking if the resulting IP is in a private or reserved range using FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE. However, the subsequent cURL request is configured with CURLOPT_FOLLOWLOCATION = true and CURLOPT_MAXREDIRS = 3, which means the request will follow HTTP redirects without re-validating the destination IP. This issue has been fixed in version 4.6.1.
Weakness
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.