My shared hosting provider uses PHP 5.2.5, which was released at the end of 2007. I would like to know the security holes of PHP 5.2.5. Where I can get them?
PHP ChangeLog ... check anything above 5.2.5 in 5.2.x series only..
Curiously enough, specific security issues aren't often published (otherwise they'd be very easy to exploit), but you can generally get an idea from the changelogs for subsequent releases.
Vulnerabilities are on this page: