The vulnerability is caused by mishandling of unknown XML elements when parsing OOXML document files. Specially crafted documents can be used for denial-of-service attacks. Further exploits are possible but have not been verified.
Apache OpenOffice 3.4 users are advised to upgrade to Apache OpenOffice 4.0. Users who are unable to upgrade immediately should be cautious when opening untrusted documents.
The Apache OpenOffice security team credits Jeremy Brown of Microsoft Vulnerability Research as the discoverer of this flaw.