SSO login with cross-domain fails on Firefox and Safari — works on Chrome only

[normanaranez]

Checklist

• The issue can be reproduced in the auth0-react sample app (or N/A).
• I have looked into the Readme, Examples, and FAQ and have not found a suitable solution or answer.
• I have looked into the API documentation and have not found a suitable solution or answer.
• I have searched the issues and have not found a suitable solution or answer.
• I have searched the Auth0 Community forums and have not found a suitable solution or answer.
• I agree to the terms within the Auth0 Code of Conduct.

Description

Description

When users attempt to log in using a different domain (cross-domain SSO), the authentication flow works correctly on Chrome but silently fails on Firefox and Safari. This appears to be related to third-party cookie restrictions and ITP (Intelligent Tracking Prevention) enforced by these browsers.

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Browser behavior

Browser	Status	Notes
Chrome	✅ Working	SSO completes successfully
Firefox	❌ Broken	SSO fails silently
Safari	❌ Broken	SSO fails silently

Configuration

<Auth0Provider
  domain="YOUR_AUTH0_DOMAIN"
  clientId="YOUR_CLIENT_ID"
  authorizationParams={{
    redirect_uri: window.location.origin,
  }}
>
  <App />
</Auth0Provider>

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Expected behavior

SSO should work consistently across all major browsers. A user authenticated on app.example.com should be recognized when visiting portal.otherdomain.com without needing to re-authenticate.

Actual behavior

Firefox and Safari block the third-party session cookie set by Auth0 due to privacy restrictions (ETP / ITP), causing the SSO check to fail. The user is redirected to the login page or gets stuck in a redirect loop.

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Environment

Package:   @auth0/auth0-react
Version:   ^2.17.0
Browser:   Firefox Latest / Safari Latest
OS:        macOS / Windows
Framework: React 19.1.0

Reproduction

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Steps to reproduce

1. Configure Auth0Provider with a primary domain (e.g. app.example.com)
2. Log in from a second domain (e.g. portal.otherdomain.com) that shares the same Auth0 tenant
3. Open Firefox or Safari — ensure Enhanced Tracking Protection (Firefox) or ITP (Safari) is active
4. Attempt the SSO login flow
5. Observe: on Chrome the user is authenticated. On Firefox/Safari the session is not recognized and authentication fails or loops

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Additional context

No response

auth0-react version

2.17.0

React version

19.1.0

Which browsers have you tested in?

Chrome