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# Unsanitized user input in HTTP response (XSS)

## Overview

* **Rule ID**: `javascript_express_cross_site_scripting`
* **Applicable Languages**: Javascript
* **Weakness ID**: CWE-79

## Description

Including unsanitized user input in HTTP responses exposes your application to cross-site scripting (XSS) attacks. This vulnerability allows attackers to inject malicious scripts into web pages viewed by other users, posing a significant security risk.

## Remediation Guidelines

* **Do not** include user input directly in a response, as this can lead to XSS vulnerabilities.

  ```javascript
  res.send(req.body.data); // unsafe

  ```
* **Instead, sanitize user input before including it in a response**. Use library functions or frameworks designed for input sanitization to ensure that user data cannot be interpreted as executable code.

## References

* [**OWASP Cross-Site Scripting (XSS) Cheatsheet**](https://cheatsheetseries.owasp.org/cheatsheets/Cross_Site_Scripting_Prevention_Cheat_Sheet.html)
* [**CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')**](https://cwe.mitre.org/data/definitions/79.html)
* [**OWASP Top 10: A03:2021 - Injection**](https://owasp.org/Top10/A03_2021-Injection/)

## Configuration

To omit this rule during a scan, and to provide you with continuous 24/7 code-level scanning, you can employ our [**SAST TOOL**](https://scopy.sec1.io/login)