Vulnerability Description
n8n is an open source workflow automation platform. Prior to version 2.8.0, when the `N8N_SKIP_AUTH_ON_OAUTH_CALLBACK` environment variable is set to `true`, the OAuth callback handler skips ownership verification of the OAuth state parameter. This allows an attacker to trick a victim into completing an OAuth flow against a credential object the attacker controls, causing the victim's OAuth tokens to be stored in the attacker's credential. The attacker can then use those tokens to execute workflows in their name. This issue only affects instances where `N8N_SKIP_AUTH_ON_OAUTH_CALLBACK=true` is explicitly configured (non-default). The issue has been fixed in n8n version 2.8.0. Users should upgrade to this version or later to remediate the vulnerability. If upgrading is not immediately possible, administrators should consider the following temporary mitigations: Avoid enabling `N8N_SKIP_AUTH_ON_OAUTH_CALLBACK=true` unless strictly required, and/ or restrict access to the n8n instance to fully trusted users only. These workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| N8N | N8N | < 2.8.0 |
Related Weaknesses (CWE)
References
- https://github.com/n8n-io/n8n/security/advisories/GHSA-vpgc-2f6g-7w7xVendor AdvisoryMitigation
FAQ
What is CVE-2026-33720?
CVE-2026-33720 is a vulnerability with a CVSS score of 4.2 (MEDIUM). n8n is an open source workflow automation platform. Prior to version 2.8.0, when the `N8N_SKIP_AUTH_ON_OAUTH_CALLBACK` environment variable is set to `true`, the OAuth callback handler skips ownership...
How severe is CVE-2026-33720?
CVE-2026-33720 has been rated MEDIUM with a CVSS base score of 4.2/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-33720?
Check the references section above for vendor advisories and patch information. Affected products include: N8N N8N.