AzuraCast before 0.23.8 Server-Side Request Forgery via Remote Relay URL

AzuraCast (Composer package azuracast/azuracast) before 0.23.8 validates a station's "Remote Relay" URL only for URL syntax and an http/https scheme (Utilities\Urls::parseUserUrl, used by StationRemote::getUrlAsUri) and performs no host or IP address restriction. A user holding only the station-scoped RemoteRelays permission can therefore set a Remote Relay URL pointing at loopback, private-network, or cloud-metadata addresses (e.g. http://127.0.0.1:<port>/ or http://169.254.169.254/latest/meta-data/), and AzuraCast's periodic background Now Playing sync (AbstractRemote::getNowPlayingAsync) will automatically and repeatedly issue HTTP requests to that address, resulting in server-side request forgery against internal resources. This affects the main branch as of commit bcf8754eef3a268ad82c3db4d81f7920c3c28b56 (2026-07-31); no patched version is available at the time of the advisory.