The Hardened-PHP Project has posted two new advisories today, both dealing with WordPress issues - one is a trackback problem with decoding the charset and the other an XSS vulnerability.
The first advisory notes that:
While testing WordPress it was discovered that WordPress supports trackbacks in different charsets when PHP's mbstring extension is installed. This feature can be abused to bypass WordPress's SQL parameter escaping which leads to an SQL injection vulnerability that can result in a compromise of the admin account and end in a server compromise.
The second advisory talks about a problem with the WordPress admin interface that leaves it open to cross-site scripting issues.
The WordPress group has already released an updated version to resolve both of these issues. It is highly recommended that you update your installation immediately to prevent the exploits of either of these vulnerabilities.