tables/apr_hash.c in the Apache Portable Runtime (APR) library through 1.4.5 computes hash values without restricting the ability to trigger hash collisions predictably, which allows context-dependent attackers to cause a denial of service (CPU consumption) via crafted input to an application that maintains a hash table.
http://openwall.com/lists/oss-security/2012/02/08/3
http://openwall.com/lists/oss-security/2012/02/09/1
http://secunia.com/advisories/47862
https://exchange.xforce.ibmcloud.com/vulnerabilities/73096
http://svn.apache.org/viewvc?rev=1231605&view=rev
http://www.mandriva.com/security/advisories?name=MDVSA-2012:019