Koel: Authenticated Blind SSRF via Subsonic Podcast Channel Creation

Koel is a free, open-source music streaming solution. Prior to 9.7.0, the Subsonic-compatible createPodcastChannel.view route accepts an authenticated user's private URL because app/Http/Requests/Subsonic/CreatePodcastChannelRequest.php does not apply the SafeUrl validation used by the regular podcast API. app/Http/Controllers/Subsonic/CreatePodcastChannelController.php passes the URL to app/Services/Podcast/PodcastService.php, where PodcastService::addPodcast() and createParser() invoke Poddle::fromUrl() during channel creation, causing immediate server-side requests to loopback, Docker bridge, or RFC1918 HTTP destinations. The confirmed impact is blind internal request execution because generic response-body exfiltration was not demonstrated through this route. This issue is fixed in version 9.7.0.