FreeBSD 5.1 and earlier, and Mac OS X before 10.3.4, allows remote attackers to cause a denial of service (resource exhaustion of memory buffers and system crash) via a large number of out-of-sequence TCP packets, which prevents the operating system from creating new connections.
https://exchange.xforce.ibmcloud.com/vulnerabilities/15369
http://www.securityfocus.com/bid/9792
http://www.kb.cert.org/vuls/id/395670
http://www.idefense.com/application/poi/display?id=78&type=vulnerabilities
http://lists.seifried.org/pipermail/security/2004-May/003743.html