CVE-2009-1840: Mozilla Firefox

High severity, CVSS 9.3. EPSS: 2.2% chance of exploitation in the next 30 days.

Mozilla Firefox before 3.0.11, Thunderbird, and SeaMonkey do not check content policy before loading a script file into a XUL document, which allows remote attackers to bypass intended access restrictions via a crafted HTML document, as demonstrated by a "web bug" in an e-mail message, or web script or an advertisement in a web page.

Affected products

• Mozilla Firefox: up to and including 3.0.10; version 3.0 only; version 3.0.1 only; version 3.0.2 only; version 3.0.3 only; version 3.0.4 only; …
• Mozilla Seamonkey: any version
• Mozilla Thunderbird: any version

Published 2009-06-12. Last modified 2026-06-16.