OPAL (Open Phone Abstraction Layer) is "an implementation of various telephony and video communication protocols for use over packet based networks. It's based on code from the OpenH323 project and adds new features such as a stream based architecture, better support for re-use or removal of sub-components, and explicit support for additional protocols". A vulnerability in OPAL allows attackers to cause the framework to crash by sending it a malformed Content-Length value.

http://www.securiteam.com/unixfocus/6N00C2AK0M.html