Preface: Cryptocurrency look like myth. Someone avoid to use. But somebody like it. If Cryptocurrency only provide payment function. That is no investment value. Furthermore if someone going to transfer money will be know who is sender and recipient. If it come true, what is the result?

Background: BTCPay Server is an open source, P2P payment processor for Bitcoin and other cryptocurrencies where users can self-host their own server and effectively process their own payments.

Quick and easy setup (for individual and retail business): You just open an account on BTCpayserver. it is web GUI and internet everywhere. So, your customer can pay to you by cryptocurrency.

Users have even built web based point of sales payment solutions using the project. Physical stores can leverage the PoS app for accepting crypto payments. BTCPay Server is code, not a company. There is no third-party between a merchant and a customer. The merchant is always in full control of their funds. There are no processing or subscription fees.

Vulnerability details: BTCpayserver is vulnerable to Improper Neutralization of Input During Web Page Generation (‘Cross-site Scripting’). So called Cross-site Scripting, btcpayserver” stored XSS, also known as persistent XSS. In stored XSS, the malicious code is stored on the server of the application. Stored XSS is possible only when the application is designed to store user input. The attacker would inject the code through requests to the application.

Cause: During page generation, the application does not prevent the data from containing content that is executable by a web browser, hsuch as JavaScript, HTML tags, HTML attributes. For details of vulnerability , please refer to attached diagram.

Official details: – https://nvd.nist.gov/vuln/detail/CVE-2021-3830