modules/arch/win32/mod_isapi.c in mod_isapi in the Apache HTTP Server 2.0.37 through 2.0.63, 2.2.0 through 2.2.14, and 2.3.x before 2.3.7, when running on Windows, does not ensure that request processing is complete before calling isapi_unload for an ISAPI .dll module, which allows remote attackers to execute arbitrary code via unspecified vectors related to a crafted request, a reset packet, and "orphaned callback pointers."
https://www.exploit-db.com/exploits/11650
https://exchange.xforce.ibmcloud.com/vulnerabilities/56624
http://www.vmware.com/security/advisories/VMSA-2010-0014.html
http://www.senseofsecurity.com.au/advisories/SOS-10-002
http://www.oracle.com/technetwork/topics/security/cpujuly2013-1899826.html
http://www.kb.cert.org/vuls/id/280613