lack of input validation that can lead Denial of Service (DOS)

Hi Security Team, ## Summary: There is no limit to the number of characters in the issue comments, which allows a DoS attack. The DoS attack affects server-side. ## Description On the input form of Username in `https://twitter.com/settings/screen_name` there's no Input validation using this you can send more payload and may cause of Denial of service or error code 500 Internal Server Error/Internal Error ## Proof of Concept 1. First login your twitter account 2. Go to the Settings of your account 3. Click Username 4. Change your username and put the payload then submit And the response was pop up and say. ==Something went wrong, but don't fret --- it's not your fault.== and the response code on the server side is `500 Internal Server Error` Kindly check 2 uploaded photo for my additional Proof of Concept ### Remediation: Implementing input validation Validating free-form Unicode text Define the allowed set of characters to be accepted. Minimum and maximum value range Supporting Material/References: payload.txt Thank you! Regards ## Impact Attacker can perform a DOS because of lack of input validation