CVE-2026-77073: n8n before 2.34.1 Cross-Project Credential Access via MCP
n8n versions before 2.34.1 contain a credential validation bypass in the MCP createworkflowfromcode tool when authentication type is set to an expression. Attackers with a valid MCP Bearer API key and knowledge of a target credential ID can persist unauthorized cross-project credential references on workflows in different projects.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
n8nto a version that resolves this vulnerability.Fixed in 2.34.1 - Compensating control
For n8n versions before 2.34.1, avoid setting authentication type to an expression in the MCP create_workflow_from_code tool to prevent the credential validation bypass.
Event History
Frequently Asked Questions
Who can exploit this issue?
An attacker needs a valid MCP Bearer API key and knowledge of a credential ID belonging to a target project. The issue enables unauthorized credential references to be persisted in workflows in other projects.
Are all authentication configurations affected?
The described validation bypass applies when the authentication type is set to an expression in the MCP create_workflow_from_code tool.
What versions should be remediated?
n8n versions before 2.34.1 are affected. Upgrade to version 2.34.1 or later.