Apache Vysper: Unbounded allocation

**UNSUPPORTED WHEN ASSIGNED**  Unbounded allocation in XML parsing in Apache Vysper; all versions, may lead to an out of memory condition.

This issue affects all versions of Apache Vysper. Apache Vysper is an XMPP (Jabber) server library.

As this project is retired, we do not plan to release a version that fixes this issue. Users are recommended to find an alternative.