I have a pretty old site which I've just recently upgraded to 2.11.6. Everything works well, except that I can't update templates (in the CP) if they contain <script>, <meta>, <link>, or <style> tags. If I try, I get the error
403 Forbidden A potentially unsafe operation has been detected in your request to this site.
Has anyone seen anything like this, or have an idea where I might check to solve this?
Edit/Additional information: While looking into Derek's suggestion about mod_security, I remembered that I had set this site to use PHP7 as a test, and sure enough, when I set it back to 5.6, I can update templates fine. So it's something to do with PHP7, but not sure what yet.