CVE-2006-2783: Mozilla Firefox

Medium severity, CVSS 4.3. EPSS: 1.7% chance of exploitation in the next 30 days.

Mozilla Firefox and Thunderbird before 1.5.0.4 strip the Unicode Byte-order-Mark (BOM) from a UTF-8 page before the page is passed to the parser, which allows remote attackers to conduct cross-site scripting (XSS) attacks via a BOM sequence in the middle of a dangerous tag such as SCRIPT.

Affected products

• Mozilla Firefox: up to and including 1.5.0.3
• Mozilla Thunderbird: up to and including 1.5.0.3

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