heartbeat.c in heartbeat before 2.0.6 sets insecure permissions in a shmget call for shared memory, which allows local users to cause an unspecified denial of service via unknown vectors, possibly during a short time window on startup.
http://www.vupen.com/english/advisories/2006/2994
http://www.ubuntu.com/usn/usn-326-1
http://www.securityfocus.com/bid/19186
http://www.mandriva.com/security/advisories?name=MDKSA-2006:142
http://www.mail-archive.com/linux-ha-cvs%40lists.linux-ha.org/msg00753.html
http://www.linux-ha.org/_cache/SecurityIssues__sec03.txt
http://www.debian.org/security/2006/dsa-1128
http://securitytracker.com/id?1016602
http://security.gentoo.org/glsa/glsa-200608-23.xml
http://secunia.com/advisories/21629
http://secunia.com/advisories/21521
http://secunia.com/advisories/21240
http://secunia.com/advisories/21231
http://secunia.com/advisories/21162
http://cvs.linux-ha.org/viewcvs/viewcvs.cgi/linux-ha/heartbeat/heartbeat.c?r1=1.513&r2=1.514