Drupal 5.x before 5.13 and 6.x before 6.7 does not delete all related content when an input format is deleted, which prevents the content from being properly filtered and allows remote attackers to conduct cross-site scripting (XSS) attacks via unspecified vectors.

Cross-site scripting (XSS) vulnerability in Drupal 5.x before 5.12 and 6.x before 6.6 allows remote authenticated users with create book content or edit node book hierarchy permissions to inject arbitrary web script or HTML via the book page title.

includes/bootstrap.inc in Drupal 5.x before 5.12 and 6.x before 6.6, when the server is configured for "IP-based virtual hosts," allows remote attackers to include and execute arbitrary files via the HTTP Host header.

Drupal, probably 5.10 and 6.4, does not set the secure flag for the session cookie in an https session, which can cause the cookie to be sent in http requests and make it easier for remote attackers to capture this cookie.