Applio allows SSRF and file write in model_download.py

Applio is a voice conversion tool. Versions 3.2.7 and prior are vulnerable to server-side request forgery (SSRF) in `model_download.py` (line 195 in 3.2.7). The blind SSRF allows for sending requests on behalf of Applio server and can be leveraged to probe for other vulnerabilities on the server itself or on other back-end systems on the internal network, that the Applio server can reach. The blind SSRF can also be coupled with a arbitrary file read (e.g., CVE-2025-27784) to read files from hosts on the internal network, that the Applio server can reach, which would make it a full SSRF. As of time of publication, no known patches are available.