CVE-2005-3420: Phpbb Group Phpbb

High severity, CVSS 7.5. EPSS: 2.4% chance of exploitation in the next 30 days.

usercp_register.php in phpBB 2.0.17 allows remote attackers to modify regular expressions and execute PHP code via the signature_bbcode_uid parameter, as demonstrated by injecting an "e" modifier into a preg_replace statement.

Affected products

• Phpbb Group Phpbb: version 2.0.0 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; …

Published 2005-11-01. Last modified 2026-06-16.