---
title: "WEB-COR-001 Cross-Origin Resource Sharing Allows Any Origin With Credentials"
canonical: https://openvapt.com/checks/WEB-COR-001.html
html: https://openvapt.com/checks/WEB-COR-001.html
site: OpenVAPT, https://openvapt.com/
license: OpenVAPT Source-Available Licence 1.3, https://openvapt.com/legal/licence-text.html
modified: 2026-10-14
version: 0.1.0-alpha.6
---

# WEB-COR-001 Cross-Origin Resource Sharing Allows Any Origin With Credentials

Checks the home page's CORS headers for a wildcard origin combined with credentials, or an origin of null.

- Domain: Web Apps
- Severity: Medium
- Control category: Web Application Security
- Fix effort: low
- CVSS v3.1 vector: `CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N`
- CIS Controls v8: 16.7
- NIST CSF 2.0: PR.PS-01
- CWE: CWE-942
- OWASP Top 10 2021: A05:2021, A01:2021
- OWASP ASVS 4.0.3: 14.5.3
- OWASP WSTG v4.2: WSTG-CLNT-07
- NIST SP 800-53 Rev. 5: AC-4, CM-6

## Why It Matters

A permissive CORS policy can let any website read responses on behalf of a logged-in visitor, exposing personal data and tokens.

## How It Detects

Reads Access-Control-Allow-Origin and Access-Control-Allow-Credentials on each site's home page. '*' with credentials true, or 'null', fails. Origin reflection needs crafted requests and is outside this read-only check.

## How to Fix

Return Access-Control-Allow-Origin only for an explicit allow-list of trusted origins, never '*' or 'null' together with credentials, and add Vary: Origin.

## How to Verify

```
curl -sI https://<site>/ | grep -i access-control
```

## Learn the Theory

- [P5 Web Security Headers and Cookies](https://openvapt.com/academy/p5.md)

## References

- [OWASP WSTG-CLNT-07, Testing Cross Origin Resource Sharing](https://wstg.owasp.org/v4.2/4-Web_Application_Security_Testing/11-Client-side_Testing/07-Testing_Cross_Origin_Resource_Sharing/)
- [MDN Web Docs, Access-Control-Allow-Origin](https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/Access-Control-Allow-Origin)

## Source Code

https://github.com/OpenVAPT/openvapt/blob/574f7f3333c44b75a3c649e2d93a76d507f75adf/internal/checks/web/docroot.go

Run it: `openvapt scan --only WEB-COR-001`. Read it offline: `openvapt explain WEB-COR-001`.

---

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