Cannot access theme folder: WordPress sets bad permissions?

Hey together,

I have alwyas uploaded my themes via the admin panel.

Now, I needed to add a file to the theme (category.php) and wanted to access the theme folder. That is when I found out, that wordpress sets the permissions for my uploaded themes to rwxr-x–x. The owner is not me, (I don’t even know, why that is).

So the result is, I cannot access the folder and I cannot change the permissions. Anybody who can help here?

Many thanks!