Multiple integer overflows in the HMI application in DATAC RealFlex RealWin 2.1 (Build 6.1.10.10) and earlier allow remote attackers to execute arbitrary code via crafted (1) On_FC_MISC_FCS_MSGBROADCAST and (2) On_FC_MISC_FCS_MSGSEND packets, which trigger a heap-based buffer overflow.
http://www.vupen.com/english/advisories/2011/0742
http://www.us-cert.gov/control_systems/pdf/ICS-ALERT-11-080-04.pdf