Due to a bug in either FF 17.0 or ckeditor a dangerous, I dare say vulnerability, is made available to users using FF 17.0. The behavior is described here:
https://support.mozilla.org/en-US/questions/942438?page=2
A workaround is available, but I didn't pursue, which requires editing of some portion of fckeditor browser checking. My workaround was to force users to update to a version of Firefox other than 17.0. I preferably directed them to the Extended Support Release version using javascript since we are an enterprise environment.
I plan to pursue update to CKEditor, meanwhile what options do I have to verify that for any update to a web browser I'm not exposing my edit enabled pages to source code changes?