CVE-2009-1838: Mozilla Firefox

High severity, CVSS 9.3. EPSS: 4.8% chance of exploitation in the next 30 days.

The garbage-collection implementation in Mozilla Firefox before 3.0.11, Thunderbird before 2.0.0.22, and SeaMonkey before 1.1.17 sets an element's owner document to null in unspecified circumstances, which allows remote attackers to execute arbitrary JavaScript with chrome privileges via a crafted event handler, related to an incorrect context for this event handler.

Affected products

• Mozilla Firefox: up to and including 3.0.10; version 0.1 only; version 0.2 only; version 0.3 only; version 0.4 only; version 0.5 only; …
• Mozilla Seamonkey: up to and including 1.1.16; version 1.0 only; version 1.0.1 only; version 1.0.3 only; version 1.0.4 only; version 1.0.6 only; …
• Mozilla Thunderbird: up to and including 2.0.0.19; version 0.1 only; version 0.2 only; version 0.3 only; version 0.4 only; version 0.5 only; …

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