In FusionPBX up to v4.5.7, the file app/musiconhold/musiconhold.php uses an unsanitized "file" variable coming from the URL, which takes any pathname (base64 encoded) and allows a download of it.
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2019-16990.json"
[ { "events": [ { "introduced": "0" }, { "last_affected": "4.5.7" } ] } ]