An updated thunderbird package that fixes several security issues is now available for Red Hat Enterprise Linux 5 and 6. The Red Hat Security Response Team has rated this update as having important security impact. Common Vulnerability Scoring System base scores, which give detailed severity ratings, are available for each vulnerability from the CVE links in the References section. Mozilla Thunderbird is a standalone mail and newsgroup client. Several flaws were found in the processing of malformed content. Malicious content could cause Thunderbird to crash or, potentially, execute arbitrary code with the privileges of the user running Thunderbird. A flaw was found in the way Same Origin Wrappers were implemented in Thunderbird. Malicious content could use this flaw to bypass the same-origin policy and execute arbitrary code with the privileges of the user running Thunderbird. A flaw was found in the embedded WebGL library in Thunderbird. Malicious content could cause Thunderbird to crash or, potentially, execute arbitrary code with the privileges of the user running Thunderbird. Note: This issue only affected systems using the Intel Mesa graphics drivers. An out-of-bounds write flaw was found in the embedded Cairo library in Thunderbird. Malicious content could cause Thunderbird to crash or, potentially, execute arbitrary code with the privileges of the user running Thunderbird. A flaw was found in the way Thunderbird handled the JavaScript history functions. Malicious content could cause a page to be displayed that has a baseURI pointing to a different site, allowing cross-site scripting and phishing attacks. Red Hat would like to thank the Mozilla project for reporting these issues. Upstream acknowledges Olli Pettay, Jesse Ruderman, Boris Zbarsky, Christian Holler, Milan Sreckovic, Joe Drew, Cody Crews, miaubiz, Abhishek Arya, and Mariusz Mlynski as the original reporters of these issues. Note: All issues except CVE-2013-0800 cannot be exploited by a specially-crafted HTML mail message as JavaScript is disabled by default for mail messages. They could be exploited another way in Thunderbird, for example, when viewing the full remote content of an RSS feed. All Thunderbird users should upgrade to this updated package, which contains Thunderbird version 17.0.5 ESR, which corrects these issues. After installing the update, Thunderbird must be restarted for the changes to take effect.