Opencast still publishes global system account credentials

Opencast is a free, open-source platform to support the management of educational audio and video content. Prior to version 17.6, Opencast would incorrectly send the hashed global system account credentials (ie: org.opencastproject.security.digest.user and org.opencastproject.security.digest.pass) when attempting to fetch mediapackage elements included in a mediapackage XML file. A previous CVE prevented many cases where the credentials were inappropriately sent, but not all. Anyone with ingest permissions could cause Opencast to send its hashed global system account credentials to a url of their choosing. This issue is fixed in Opencast 17.6.