How to add Cross-Origin-Resource-Policy on Vercel

Last updated November 11, 2026 · Reviewed by a CISSP-certified security practitioner

To add Cross-Origin-Resource-Policy on Vercel, set the header in vercel.json with the value same-origin. Stops other sites from loading your resources. Commit and redeploy; headers apply on the next deployment. Then confirm it with curl -I or a free FixSecurityHeaders scan.

What does Cross-Origin-Resource-Policy do?

CORP tells browsers which origins may embed your images, scripts and other resources.

Risk if missing: Other sites can embed your resources and use side channels to leak data.

What is the Vercel configuration?

Add this to vercel.json:

vercel.json

{
  "headers": [
    {
      "source": "/(.*)",
      "headers": [
        {
          "key": "Cross-Origin-Resource-Policy",
          "value": "same-origin"
        }
      ]
    }
  ]
}

How do I add it step by step?

Open vercel.json.
Paste the Cross-Origin-Resource-Policy configuration shown below.
Commit and redeploy; headers apply on the next deployment.
Run curl -I https://yourdomain.com and look for the cross-origin-resource-policy line.
Scan your site on FixSecurityHeaders to confirm the grade improved.

How do I verify it worked?

terminal

curl -sI https://yourdomain.com | grep -i "cross-origin-resource-policy"
# expected:
# cross-origin-resource-policy: same-origin

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What are the common mistakes?

Public CDNs and assets meant for embedding should use cross-origin.
vercel.json headers don't apply to Next.js middleware responses — set them in next.config.js for Next apps.
The source pattern "/(.*)" matches every path.

Quick reference

Header	`Cross-Origin-Resource-Policy`
Recommended value	`same-origin`
Stack	Vercel
Where	vercel.json
Compliance	OWASP ASVS V14.4

FAQ

What value should I use for Cross-Origin-Resource-Policy?

A safe default is same-origin. Public CDNs and assets meant for embedding should use cross-origin.

Why isn't Cross-Origin-Resource-Policy showing up on Vercel?

vercel.json headers don't apply to Next.js middleware responses — set them in next.config.js for Next apps. Also clear any CDN or page cache, and check you edited the config that actually serves your domain.

Does Cross-Origin-Resource-Policy affect SEO or performance?

No measurable performance cost — it's a few bytes per response. It doesn't affect rankings directly, but a misconfigured policy can break page resources, so test before enforcing.

Which compliance frameworks reference Cross-Origin-Resource-Policy?

OWASP ASVS V14.4.