Risk: High
An important update by the Fedora Security Response Team has been released for Thunderbird package. It ffixes various bugs and is now available for Fedora Core 3.
A bug was found in the way Thunderbird processes certain international domain names. An attacker could create a specially crafted HTML file, which when viewed by the victim would cause Thunderbird to crash or possibly execute arbitrary code. The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the name CAN-2005-2871 to this issue.
A bug was found in the way Thunderbird processes certain Unicode sequences. It may be possible to execute arbitrary code as the user running Thunderbird if the user views a specially crafted Unicode sequence. (CAN-2005-2702)
A bug was found in the way Thunderbird makes XMLHttp requests. It is possible that a malicious web page could leverage this flaw to exploit other proxy or server flaws from the victim's machine. It is also possible that this flaw could be leveraged to send XMLHttp requests to hosts other than the originator; the default behaviour of the browser is to disallow this. (CAN-2005-2703)
A bug was found in the way Thunderbird implemented its XBL interface. It may be possible for a malicious web page to create an XBL binding in such a way that would allow arbitrary JavaScript execution with chrome permissions. Please note that in Thunderbird 1.0.6 this issue is not directly exploitable and will need to leverage other unknown exploits. (CAN-2005-2704)
An integer overflow bug was found in Thunderbird's JavaScript engine. Under favourable conditions, it may be possible for a malicious mail message to execute arbitrary code as the user running Thunderbird. Please note that JavaScript support is disabled by default in Thunderbird. (CAN-2005-2705)
A bug was found in the way Thunderbird displays about: pages. It is possible for a malicious web page to open an about: page, such as about:mozilla, in such a way that it becomes possible to execute JavaScript with chrome privileges. (CAN-2005-2706)
A bug was found in the way Thunderbird opens new windows. It is possible for a malicious web site to construct a new window without any user interface components, such as the address bar and the status bar. This window could then be used to mislead the user for malicious purposes. (CAN-2005-2707)
A bug was found in the way Thunderbird processes URLs passed to it on the command line. If a user passes a malformed URL to Thunderbird, such as clicking on a link in an instant messaging program, it is possible to execute arbitrary commands as the user running Thunderbird. (CAN-2005-2968)
Besides Fedora, Ubuntu, Red Hat, and Debian have also issued updates for their versions of Thunderbird.