Mozilla · Thunderbird · CVE-2009-4629
**Name of the Vulnerable Software and Affected Versions**
Mozilla Necko versions used in Thunderbird 3.0.1, SeaMonkey, and other applications
**Description**
The issue allows remote attackers to determine the network location of the application's user by logging DNS requests. This is demonstrated by DNS requests triggered by reading text/plain e-mail messages in Thunderbird. The problem arises because Mozilla Necko performs DNS prefetching even when the application type is set for mail or editor.
**Recommendations**
For Thunderbird 3.0.1, consider disabling DNS prefetching to prevent exploitation.
For SeaMonkey, restrict DNS prefetching for mail and editor application types until a fix is available.
As a temporary workaround, avoid reading suspicious text/plain e-mail messages in Thunderbird until the issue is resolved.