Wordpress before 2.8.3 does not check capabilities for certain actions, which allows remote attackers to make unauthorized edits or additions via a direct request to (1) edit-comments.php, (2) edit-pages.php, (3) edit.php, (4) edit-category-form.php, (5) edit-link-category-form.php, (6) edit-tag-form.php, (7) export.php, (8) import.php, or (9) link-add.php in wp-admin/.
http://www.openwall.com/lists/oss-security/2009/08/04/5
http://www.debian.org/security/2009/dsa-1871
http://wordpress.org/development/2009/08/wordpress-2-8-3-security-release/