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. It was found that the RHSA-2011:0910 update did not correctly fix the CVE-2011-1005 issue, a flaw in the method for translating an exception message into a string in the Exception class. A remote attacker could use this flaw to bypass safe level 4 restrictions, allowing untrusted code to modify arbitrary, trusted strings, which safe level 4 restrictions would otherwise prevent. The CVE-2012-4481 issue was discovered by Vit Ondruch of Red Hat. All users of Ruby are advised to upgrade to these updated packages, which contain backported patches to resolve these issues.