Cisco Unity Connection before 7.1.5b(Su5), 8.0 and 8.5 before 8.5.1(Su3), and 8.6 before 8.6.2 allows remote attackers to cause a denial of service (services crash) via a series of crafted TCP segments, aka Bug ID CSCtq67899.
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20120229-cuc