Updated firefox packages that fix several security issues are now available for Red Hat Enterprise Linux 5 and 6. The Red Hat Security Response Team has rated this update as having critical 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. Description Mozilla Firefox is an open source web browser. XULRunner provides the XUL Runtime environment for Mozilla Firefox. Several flaws were found in the processing of malformed web content. A web page containing malicious content could cause Firefox to crash or, potentially, execute arbitrary code with the privileges of the user running Firefox. A buffer overflow flaw was found in the way Firefox handled GIF images. A web page containing a malicious GIF image could cause Firefox to crash or, possibly, execute arbitrary code with the privileges of the user running Firefox. A flaw was found in the way the Style Inspector tool in Firefox handled certain Cascading Style Sheets . Running the tool