CVE-2011-2378: Mozilla Firefox

High severity, CVSS 10.0. EPSS: 5.6% chance of exploitation in the next 30 days.

The appendChild function in Mozilla Firefox before 3.6.20, Thunderbird 3.x before 3.1.12, SeaMonkey 2.x, and possibly other products does not properly handle DOM objects, which allows remote attackers to execute arbitrary code via unspecified vectors that lead to dereferencing of a "dangling pointer."

Affected products

• Mozilla Firefox: up to and including 3.6.19; version 1.0 only; version 1.0.1 only; version 1.0.2 only; version 1.0.3 only; version 1.0.4 only; …
• Mozilla Seamonkey: version 2.0 only; version 2.0.1 only; version 2.0.2 only; version 2.0.3 only; version 2.0.4 only; version 2.0.5 only; …
• Mozilla Thunderbird: version 3.0 only; version 3.0.1 only; version 3.0.2 only; version 3.0.3 only; version 3.0.4 only; version 3.0.5 only; …

Published 2011-08-18. Last modified 2026-06-16.