Understanding the n8n Credential Exfiltration Vulnerability (CVE-2026-85166)
A significant security flaw has been identified in n8n, an open-source workflow automation platform. This vulnerability, tracked as CVE-2026-85166, could allow unauthorized individuals to gain access to sensitive credentials, posing a serious risk to data security. The issue lies in how n8n handles credential references within its inline workflow JSON, specifically in nodes designed to execute sub-workflows, such as the Workflow Tool node.
Under certain conditions, an attacker could craft a malicious workflow that appears harmless but secretly references credentials they don’t own. If this workflow is then executed by a user who does possess those credentials, the attacker’s sub-workflow could resolve the hidden secrets and transmit them to an endpoint controlled by the attacker. While the attacker never directly possesses the credentials within n8n, this method enables their exfiltration.
CVE Details
Product: n8n
Published Date: September 3, 2026
Severity: High
Status: Analyzed
Affected Products
The vulnerability impacts n8n versions before 2.35.4 and 2.36.x before 2.36.2. Users running any n8n instance within these version ranges are advised to take immediate action.
Current Status
The vulnerability has been officially “Analyzed” and publicly disclosed. This means the details are known, and solutions have been developed by the vendor.
Severity Level
This vulnerability is rated as High severity. This rating reflects the potential for serious consequences if exploited, primarily due to the risk of sensitive credential exfiltration. While the attacker doesn’t directly gain control of the n8n system, the ability to steal credentials can lead to unauthorized access to other linked systems and services, causing significant damage and compromise.
Possible Solutions
The good news is that n8n has already released patches to address this issue. To protect your n8n instances, you should:
- Upgrade n8n: The primary solution is to upgrade your n8n installation to version 2.35.4 or later, or version 2.36.2 or later. These versions include the necessary fixes to prevent credential exfiltration.
If an immediate upgrade is not feasible, consider these temporary mitigation steps:
- Restrict Workflow Sharing: Only allow fully trusted users to share workflows. Avoid granting “Editor” access to users you do not fully trust on any shared workflows.
- Limit n8n Instance Access: Ensure that only fully trusted users have access to your n8n instance.
- Audit and Rotate Credentials: Regularly audit shared workflows for any suspicious Workflow Tool nodes that might be referencing credentials not owned by the workflow editor. If any potential exposure is detected, immediately rotate the affected credentials.
Please remember that these workarounds are not a full fix and should only be considered as short-term measures until a proper upgrade can be performed.
References
https://github.com/n8n-io/n8n/security/advisories/GHSA-4r56-g65c-fm83
https://www.vulncheck.com/advisories/n8n-before-2.36.2-credential-exfiltration-via-workflow-tool-node
