Same for me. Cannot edit and save products. Need fix urgently please.

It must be a securetyproblem. The system is blocking the acces to the database if you edit a product.

I've found a temporary solution to avoid this message:

File: system/library/security.php

Line: 120 change to this:

if (preg_match('#<[^>]*\w*\"?[^>]*>#is', $uri, $match)) {
// return true;
return false;

It seems we've increased the security settings too much in 1.2.1 version Here you have the fix guys: https://github.com/arastta/arastta/commit/17c9f5aa7492b8e0845739687256c2a445deab6c

thank-you denis,
that worked

this message was driving me crazy

i am testing Arastta on a local server, so i thought i was attacking myself

Go settings->option->Text Editor (Admin)
Change editor from Summernote to TinyMCE and it works