> For the complete documentation index, see [llms.txt](https://docs.sec1.io/user-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.sec1.io/user-docs/4-sast/2-java/unsanitized-user-input-in-access-control-allow-origin.md).

# Unsanitized user input in Access-Control-Allow-Origin

## Overview

* **Rule ID**: `java_lang_insecure_allow_origin`
* **Applicable Languages**: Java
* **Weakness ID**: CWE-346

## Description

Setting the Access-Control-Allow-Origin header with unverified user-defined input can lead to unauthorized access to sensitive data. This vulnerability exposes your application to security risks, as attackers can specify origins that gain access to resources.

## Remediation Guidelines

* **Avoid** using user input to specify the `Access-Control-Allow-Origin` header without proper validation. This practice can unintentionally provide access to sensitive information.
* If it's essential to use user input for defining origins, **ensure thorough validation** to confirm the input comes from a trusted source.
* **Implement a safelist approach** when specifying origins. Limit access to your resources to only known and trusted domains.

## References

* [**OWASP Origin & Access-Control-Allow-Origin**](https://owasp.org/www-project-web-security-testing-guide/latest/4-Web_Application_Security_Testing/11-Client-side_Testing/07-Testing_Cross_Origin_Resource_Sharing)
* [**CWE-346: Origin Validation Error**](https://cwe.mitre.org/data/definitions/346.html)
* [**OWASP Top 10: A07:2021 - Identification and Authentication Failures**](https://owasp.org/Top10/A07_2021-Identification_and_Authentication_Failures/)

## 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)