First it was sponsored themes that the WordPress guys were warning everyone about. And with regard to that, we took a stand–somewhere near the middle, by choosing to say that sponsored themes are all right, but to the extent that they are done right.

Now the worry by some camps is the proliferation of WordPress themes with security vulnerabilities, or even worse, malicious code embedded in them. Sure, sponsorship is debatable. But then malware in your theme? I’d say that’s a different thing altogether.

That means we think having malware or any malicious code in themes is bad. These include spam links, or sometimes even back-doors to your blog that let crackers (malicious hackers, that is) get into your site or server through various means like cross-site scripting.

Vulnerabilites? Well, sure, they could have been left there due to carelessness, but if a theme author intends his/her theme to have badware, then they deserve to go to WordPress theme hell.

Sometimes, malicious individuals can get a freely available theme, put in modifications, and then upload it for public download without people knowing the files have been changed.

Lorelle VanFossen (one of our star columnists over at the Blog Herald) writes about it on the Blog Herald and on her own Lorelle on WordPress blog. Of course, I don’t exactly agree with her in calling sponsored themes “evil,” but it’s a good resource that points to several sites that can check your theme for vulnerabilities.

We have a ton of themes uploaded on our Free WordPress Themes theme viewer already, and while we admit we haven’t manually scanned each of these for vulnerabilities, we are doing that. Of course, we are also still committed to quality, aside from security.

But I think this is a good piece of advice: check your themes for vulnerabilities. If you’re not too familiar with HTML, PHP or CSS, you can try this blog security scanner by blogsecurity.net. If you’re the techie type, then it pays to inspect your WP theme for suspicious code, and to make sure your WP PHP files are intact.