Vulnerability Description
n8n before 2.29.8 and 2.30.x before 2.30.1 (affected from 2.27.0, when the OAuth 2.1 consent and token-issuance flow was introduced) does not verify that the authenticated user has access to the workflow referenced as the OAuth resource. On instances with at least one active MCP Server Trigger workflow configured with n8n OAuth2 authentication, a member-level user can register an OAuth client, self-approve consent for another user's workflow, and obtain a valid token. The workflow then runs in the owner's project context with the owner's stored credentials, and the attacker can set tool inputs and read outputs (potentially including data from the owner's connected integrations), breaking user and project isolation.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| N8N | N8N | >= 2.27.0, < 2.29.8 |
Related Weaknesses (CWE)
References
- https://github.com/n8n-io/n8n/security/advisories/GHSA-q5xf-xhwf-cwqfMitigationVendor Advisory
- https://www.vulncheck.com/advisories/n8n-before-missing-oauth-authorization-checThird Party Advisory
FAQ
What is CVE-2026-65594?
CVE-2026-65594 is a vulnerability with a CVSS score of 6.5 (MEDIUM). n8n before 2.29.8 and 2.30.x before 2.30.1 (affected from 2.27.0, when the OAuth 2.1 consent and token-issuance flow was introduced) does not verify that the authenticated user has access to the workf...
How severe is CVE-2026-65594?
CVE-2026-65594 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-65594?
Check the references section above for vendor advisories and patch information. Affected products include: N8N N8N.