Affects Version/s: 7.0.X, 7.1.X, 7.2.X, Master
1) Add a Web Content Display portlet to Welcome Page
2) Create a new Basic Web Content
3) Copy all the text from the for_reproduction.txt file (containing 'a<0x03>b') and paste to CKEditor
Remove the invalid characters and the publication is successful.
The web content can't be published due to errors 'Your request failed to complete.' and 'Please enter valid content.'