Mozilla Thunderbird is a standalone mail and newsgroup client. A race condition flaw was found in the way Thunderbird handled Document Object Model element properties. An HTML mail message containing malicious content could cause Thunderbird to crash or, potentially, execute arbitrary code with the privileges of the user running Thunderbird. Note: JavaScript support is disabled by default in Thunderbird. The CVE-2010-3765 issue is not exploitable unless JavaScript is enabled. All Thunderbird users should upgrade to this updated package, which resolves this issue. All running instances of Thunderbird must be restarted for the update to take effect.