OCaml 3.12.1 and earlier 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.
openwall.com/lists/oss-security/2012/02/07/1
openwall.com/lists/oss-security/2012/02/07/2
secunia.com/advisories/47853
www.mail-archive.com/caml-list%40inria.fr/msg01477.html
www.mail-archive.com/caml-list%40inria.fr/msg01478.html
www.nruns.com/_downloads/advisory28122011.pdf
www.ocert.org/advisories/ocert-2011-003.html