n8n allows open redirects via the /signin endpoint

Impact

This is an Open Redirect (CWE-601) vulnerability in the login flow of n8n. Authenticated users can be redirected to untrusted, attacker-controlled domains after logging in, by crafting malicious URLs with a misleading redirect query parameter.

This may lead to:

• Phishing attacks by impersonating the n8n UI on lookalike domains (e.g., n8n.local.evil.com)
• Credential or 2FA theft if users are tricked into re-entering sensitive information
• Reputation risk due to the visual similarity between attacker-controlled domains and trusted ones

The vulnerability affects anyone hosting n8n and exposing the /signin endpoint to users.

Patches

The issue has been patched in 1.98.0. All users should upgrade to this version or later.

The fix introduces strict origin validation for redirect URLs, ensuring only same-origin or relative paths are allowed after login.

Patch commit: https://github.com/n8n-io/n8n/pull/16034