Updated ruby packages that fix one security issue are now available for Red Hat Enterprise Linux 5 and 6. The Red Hat Security Response Team has rated this update as having moderate security impact. A Common Vulnerability Scoring System base score, which gives a detailed severity rating, is available from the CVE link in the References section. Ruby is an extensible, interpreted, object-oriented, scripting language. It has features to process text files and to do system management tasks. A flaw was found in Ruby's SSL client's hostname identity check when handling certificates that contain hostnames with NULL bytes. An attacker could potentially exploit this flaw to conduct man-in-the-middle attacks to spoof SSL servers. Note that to exploit this issue, an attacker would need to obtain a carefully-crafted certificate signed by an authority that the client trusts. All users of Ruby are advised to upgrade to these updated packages, which contain backported patches to resolve this issue.