The Solaris pollset feature in the Event Port backend in poll/unix/port.c in the Apache Portable Runtime (APR) library before 1.3.9, as used in the Apache HTTP Server before 2.2.14 and other products, does not properly handle errors, which allows remote attackers to cause a denial of service (daemon hang) via unspecified HTTP requests, related to the prefork and event MPMs.
https://issues.apache.org/bugzilla/show_bug.cgi?id=47645
https://exchange.xforce.ibmcloud.com/vulnerabilities/53666
http://www.securityfocus.com/bid/36596
http://www.oracle.com/technetwork/topics/security/cpuapr2013-1899555.html