Drupal security advisory – The way page caching was implemented allows a denial of service attack. An attacker has to have the ability to post content on the site. He or she would then be able to poison the page cache, so that it returns cached 404 page not found errors for existing pages. If the page cache is not enabled, your site is not vulnerable. The vulnerability only affects sites running on top of MySQL.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/53476/DRUPAL-SA-2007-002.txt
Source: https://packetstormsecurity.com/files/53476/DRUPAL-SA-2007-002.txt.html