Frappe Builder versions before 1.36.1 expose a server‑side request forgery flaw in the convert_to_webp API. The endpoint accepts an image_url parameter, performs an unauthenticated HTTP GET that follows redirects without re‑validating the resulting IP address, and stores the image in a publicly readable /files/ location. This allows a low‑privilege authenticated user to point the request at internal network resources or cloud metadata endpoints, enabling data exfiltration or blind probing of internal hosts.

The affected product is Frappe Builder, any installation running a version earlier than 1.36.1 is vulnerable. The vulnerability is reported for the 'frappe:builder' suite.

The CVSS score of 6.3 indicates a medium severity vulnerability. No EPSS score is available, and the issue is not listed in the CISA KEV catalog. Because the flaw requires only a low‑privilege authenticated user and relies on an external request without proper authorization or IP validation, the likelihood of exploitation is moderate. Attackers could generate internal requests, retrieve files, and store them on the public file server, effectively leaking internal data or enabling further internal reconnaissance.