Some tags in comment field brakes the whole UI.

Here's a patch.

And the patch ;)

Ok, great.
By the way, it would be nice if you commited with
git am < filename.patch
so the author would actually get the credit, as described here.

Well, maybe you could start from this patch? :)

Note, that there is an alternative method:
git commit --author="username <[username]@[uid].no-reply.drupal.org>", so for example your patch would be commited like this:
git commit --author="dereine <dereine@99340.no-reply.drupal.org>".

You can use that if the patch is not "git aware". You can tell the difference by looking at the patch:
If it has "email-like header"(like my patch above), then it's formatted correctly and you can use git am. Otherwise
you need to use the --author(or, better, teach the patcher to properly format his/her patches).

Proper authoring is very nice way of saying "thanks", since it makes the project show on authors profile(and, of course, is the proper "git" way of doing things).

Easily fixable:

git revert HEAD
git am <Script-tag-in-comment-field-blows-ui-1397944-2.patch

Yes, proper authoring introduces some overhead but it's the right thing to do to encourage contribution.