(RHSA-2011:1341) Critical: firefox security update

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. (CVE-2011-2995)

A flaw was found in the way Firefox processed the “Enter” keypress event. A
malicious web page could present a download dialog while the key is
pressed, activating the default “Open” action. A remote attacker could
exploit this vulnerability by causing the browser to open malicious web
content. (CVE-2011-2372)

A flaw was found in the way Firefox handled Location headers in redirect
responses. Two copies of this header with different values could be a
symptom of a CRLF injection attack against a vulnerable server. Firefox now
treats two copies of the Location, Content-Length, or Content-Disposition
header as an error condition. (CVE-2011-3000)

A flaw was found in the way Firefox handled frame objects with certain
names. An attacker could use this flaw to cause a plug-in to grant its
content access to another site or the local file system, violating the
same-origin policy. (CVE-2011-2999)

An integer underflow flaw was found in the way Firefox handled large
JavaScript regular expressions. A web page containing malicious JavaScript
could cause Firefox to access already freed memory, causing Firefox to
crash or, potentially, execute arbitrary code with the privileges of the
user running Firefox. (CVE-2011-2998)

For technical details regarding these flaws, refer to the Mozilla security
advisories for Firefox 3.6.23. You can find a link to the Mozilla
advisories in the References section of this erratum.

All Firefox users should upgrade to these updated packages, which contain
Firefox version 3.6.23, which corrects these issues. After installing the
update, Firefox must be restarted for the changes to take effect.