I recently found this really nice tool for scanning a project's dependancies for security issues: https://security.sensiolabs.org/. You'll need to be using https://getcomposer.org/ to take advantage of it, but if you are then it's as easy as downloading the tool and running it against your composer.lock file like so:

$ php security-checker security:check /path/to/composer.lock

If there are any issues with any of the libraries you are using, you'll get a nice message telling you what the problem is and what CVE's if any impact those libraries. I've hooked this into CI for my team, so we can be sure we're not shipping code with known security holes.