Ruby is an extensible, interpreted, object-oriented, scripting language. It has features to process text files and to do system management tasks. It was discovered that Ruby"s REXML library did not properly restrict XML entity expansion. An attacker could use this flaw to cause a denial of service by tricking a Ruby application using REXML to read text nodes from specially-crafted XML content, which will result in REXML consuming large amounts of system memory. All users of Ruby are advised to upgrade to these updated packages, which contain backported patches to resolve this issue.