The Java Message Service (JMS) in IBM WebSphere Application Server (WAS) before 6.1.0.7 allows attackers to cause a denial of service via unknown vectors involving the "double release [of] a bytebuffer input stream," possibly a double free vulnerability.
http://www.vupen.com/english/advisories/2007/1282
http://www-1.ibm.com/support/docview.wss?rs=180&uid=swg27007951#6107