An updated thunderbird package that fixes one security issue is now available for Red Hat Enterprise Linux 6. The Red Hat Security Response Team has rated this update as having critical 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. Description Mozilla Thunderbird is a standalone mail and newsgroup client. A heap-based buffer overflow flaw was found in the way Thunderbird handled PNG images. An HTML mail message or remote content containing a specially-crafted PNG image could cause Thunderbird to crash or, possibly, execute arbitrary code with the privileges of the user running Thunderbird. All Thunderbird users should upgrade to this updated package, which corrects this issue. After installing the update, Thunderbird must be restarted for the changes to take effect.