1.5.1.2 was released the other day. Its just a one-line fix if you didn’t want to download a whole archive.

1. Open the wp-includes/template-functions-category.php file in a text editor like Wordpad.
2. Go to around line 103 where it says get_the_category_by_ID.
3. Create a new line after that and paste in $cat_ID = (int) $cat_ID;