CVE-2006-2776: Mozilla Firefox

High severity, CVSS 7.5. EPSS: 6.2% chance of exploitation in the next 30 days.

Certain privileged UI code in Mozilla Firefox and Thunderbird before 1.5.0.4 calls content-defined setters on an object prototype, which allows remote attackers to execute code at a higher privilege than intended.

Affected products

• Mozilla Firefox: version 0.8 only; version 0.9 only; version 0.9.1 only; version 0.9.2 only; version 0.9.3 only; version 0.10 only; …
• Mozilla Thunderbird: version 0.1 only; version 0.2 only; version 0.3 only; version 0.4 only; version 0.5 only; version 0.6 only; …

Published 2006-06-02. Last modified 2026-06-16.