CVE-2009-1309: Mozilla Firefox

Medium severity, CVSS 4.3. EPSS: 1.4% chance of exploitation in the next 30 days.

Mozilla Firefox before 3.0.9, Thunderbird, and SeaMonkey do not properly implement the Same Origin Policy for (1) XMLHttpRequest, involving a mismatch for a document's principal, and (2) XPCNativeWrapper.toString, involving an incorrect __proto__ scope, which allows remote attackers to conduct cross-site scripting (XSS) attacks and possibly other attacks via a crafted document.

Affected products

• Mozilla Firefox: up to and including 3.0.8; version 0.1 only; version 0.2 only; version 0.3 only; version 0.4 only; version 0.5 only; …
• Mozilla Seamonkey: any version
• Mozilla Thunderbird: any version

Published 2009-04-22. Last modified 2026-06-16.