Koel before version 9.7.0 contained a bug in the Subsonic‑compatible createPodcastChannel.view route. The request validator did not enforce safe‑URL filtering, allowing an authenticated user to provide a URL that was subsequently passed without sanitisation to the PodcastService. The service invoked Poddle::fromUrl(), which immediately performed a server‑side HTTP request. Because the response body was not returned to the user, the flaw is blind; an attacker can only observe that a request was made, but cannot capture the payload.

All Koel installations running any release older than 9.7.0 are affected. The vulnerability is tied specifically to the createPodcastChannel route that accepts an authenticated user’s private URL. The only vendor *product* appearing in the CNA data is Koel.

The CVSS score is 4.3, indicating a moderate severity. EPSS is not available, and the issue is not listed in the CISA KEV catalog. The attack requires authenticated access and relies on the application making outbound HTTP requests. An attacker can force the server to query arbitrary internal IPs or loopback addresses, which may reveal the existence of other services and enable further reconnaissance, but cannot directly exfiltrate responses through this exploit path.