The jabber:iq:auth implementation in IQAuthHandler.java in Ignite Realtime Openfire before 3.6.4 allows remote authenticated users to change the passwords of arbitrary accounts via a modified username element in a passwd_change action.
https://exchange.xforce.ibmcloud.com/vulnerabilities/50292
http://www.vupen.com/english/advisories/2009/1237
http://www.igniterealtime.org/builds/openfire/docs/latest/changelog.html