CVE-2006-3803: Mozilla Firefox

Medium severity, CVSS 5.1. EPSS: 4.5% chance of exploitation in the next 30 days.

Race condition in the JavaScript garbage collection in Mozilla Firefox 1.5 before 1.5.0.5, Thunderbird before 1.5.0.5, and SeaMonkey before 1.0.3 might allow remote attackers to execute arbitrary code by causing the garbage collector to delete a temporary variable while it is still being used during the creation of a new Function object.

Affected products

• Mozilla Firefox: version 1.5 only; version 1.5.0.1 only; version 1.5.0.2 only; version 1.5.0.3 only; version 1.5.0.4 only
• Mozilla Seamonkey: version 1.0 only; version 1.0.1 only; version 1.0.2 only
• Mozilla Thunderbird: version 1.5 only; version 1.5.0.2 only; version 1.5.0.4 only

Published 2006-07-27. Last modified 2026-06-16.