Hello!

If you have entered your CGPA incorrectly in the SSC CGL application form then maybe it can be considered as unintentional but it totally depends upon the SSC CGL verification process.  The window is already closed so you cannot change it.

If you cleared the exam and reached to the verification stage than you can present your orginal marksheet and explain them your issue.

You can also send a mail or written explanation to their office and Explain them your issue properly.