CVE-2009-4630: Mozilla Firefox

Medium severity, CVSS 5.0. EPSS: 1% chance of exploitation in the next 30 days.

Mozilla Necko, as used in Firefox, SeaMonkey, and other applications, performs DNS prefetching of domain names contained in links within local HTML documents, which makes it easier for remote attackers to determine the network location of the application's user by logging DNS requests. NOTE: the vendor disputes the significance of this issue, stating "I don't think we necessarily need to worry about that case."

Affected products

• Mozilla Firefox: any version
• Mozilla Seamonkey: any version
• Mozilla Thunderbird: any version

Published 2010-01-29. Last modified 2026-06-16.