CVE-2026-56776: n8n - Incorrect OAuth Scope Validation in Workflow Test Run Endpoint

Severity: high (CVSS 7.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-08 · updated 2026-10-29
Weakness: CWE-863

Description

n8n before 1.123.55, 2.25.7, and 2.26.2 contains an authorization bypass in the POST /workflows/{workflowId}/test-runs/new endpoint, which authorizes access using the workflow:read scope instead of workflow:execute. An authenticated user with read-only access to a workflow can trigger a real evaluation test run, causing the workflow to execute via the internal workflow runner and resulting in unintended outbound API calls, data mutations, or other side effects in connected downstream systems. The issue primarily affects instances using the Evaluations feature where RBAC project roles grant workflow:read without workflow:execute.

Affected products

n8n-io n8n: before 1.123.55; from 2.0.0 before 2.25.7; from 2.26.0 before 2.26.2 — fixed in 1.123.55, 2.25.7, 2.26.2
n8n-io n8n: before 1.123.55 — fixed in 1.123.55

How to fix

Upgrade to a fixed version: n8n-io n8n 1.123.55, 2.25.7, 2.26.2; n8n-io n8n 1.123.55. Check the vendor advisory for mitigations.

References

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