The core Upload module in Drupal 4.7.x before 4.7.8 and 5.x before 5.3 places the .html extension on a whitelist, which allows remote attackers to conduct cross-site scripting (XSS) attacks by uploading .html files.

The hook_comments API in Drupal 4.7.x before 4.7.8 and 5.x before 5.3 does not pass publication status, which might allow attackers to bypass access restrictions and trigger e-mail with unpublished comments from some modules, as demonstrated by (1) Organic groups and (2) Subscriptions.

Drupal 5.2 and earlier does not properly unset variables when the input data includes a numeric parameter with a value matching an alphanumeric parameter's hash value, which allows remote attackers to execute arbitrary PHP code by invoking the drupal_eval function through a callback parameter to the default URI, as demonstrated by the _menu[callbacks][1][callback] parameter. NOTE: it could be argued that this vulnerability is due to a bug in the unset PHP command (CVE-2006-3017) and the proper fix should be in PHP; if so, then this should not be treated as a vulnerability in Drupal.

Multiple cross-site scripting (XSS) vulnerabilities in Drupal 5.x before 5.2, and 4.7.x before 4.7.7, (1) allow remote attackers to inject arbitrary web script or HTML via "some server variables," including PHP_SELF; and (2) allow remote authenticated administrators to inject arbitrary web script or HTML via custom content type names.

The (1) Textimage 4.7.x before 4.7-1.2 and 5.x before 5.x-1.1 module for Drupal and the (2) Captcha 4.7.x before 4.7-1.2 and 5.x before 5.x-1.1 module for Drupal allow remote attackers to bypass the CAPTCHA test via an empty captcha element in $_SESSION.

The comment_form_add_preview function in comment.module in Drupal before 4.7.6, and 5.x before 5.1, and vbDrupal, allows remote attackers with "post comments" privileges and access to multiple input filters to execute arbitrary code by previewing comments, which are not processed by "normal form validation routines."

Multiple cross-site scripting (XSS) vulnerabilities in Drupal before 4.6.11, and 4.7 before 4.7.5, allow remote attackers to inject arbitrary web script or HTML via unspecified parameters in the (1) filter and (2) system modules. NOTE: some of these details are obtained from third party information.

Unspecified vulnerability in Drupal before 4.6.11, and 4.7 before 4.7.5, when MySQL is used, allows remote authenticated users to cause a denial of service by poisoning the page cache via unspecified vectors, which triggers erroneous 404 HTTP errors for pages that exist.