CVE-2026-33663: 
NixOS vulnerability analysis and mitigation

CVE-2026-33663 is a credential theft vulnerability in n8n, an open-source workflow automation platform, classified as "Credential Theft via Name-Based Resolution and Permission Checker Bypass in Community Edition." An authenticated user with the global:member role can exploit chained authorization flaws to steal plaintext secrets from generic HTTP credentials (httpBasicAuth, httpHeaderAuth, httpQueryAuth) belonging to other users on the same instance. The vulnerability affects n8n Community Edition versions prior to 1.123.27 (v1 branch), prior to 2.13.3, and version 2.14.0 (v2 branch); Enterprise Edition is not affected. It was disclosed on March 25, 2026, with a CVSS v4.0 score of 8.5 (High) and a CVSS v3.1 score of 6.5 (Medium) (GitHub Advisory, Github Advisory).

The root cause is CWE-639 (Authorization Bypass Through User-Controlled Key): n8n's credential pipeline contains two chained flaws. First, a name-based credential resolution path resolves credentials by name without enforcing ownership or project scope, allowing a member-role user to look up another user's credential ID. Second, the credentials permission checker incorrectly skips validation for generic HTTP credential types (httpBasicAuth, httpHeaderAuth, httpQueryAuth) during pre-execution checks, meaning these credential types bypass the authorization gate entirely. By combining these two weaknesses, an attacker can craft a workflow that references another user's credential by its resolved ID, trigger execution, and receive the decrypted plaintext secret. Native integration credential types (e.g., slackApi, openAiApi, postgres) are not affected because they are not skipped by the permission checker (GitHub Advisory, Github Advisory).

Successful exploitation allows an authenticated member-role user to decrypt and obtain plaintext HTTP credentials (basic auth, header auth, query auth) belonging to any other user on the same n8n Community Edition instance. This can lead to unauthorized access to third-party services and APIs protected by those credentials, potential data exfiltration from downstream systems, and lateral movement into dependent infrastructure. Integrity and availability of the n8n instance itself are not directly impacted, but subsequent systems protected by the stolen credentials face high confidentiality, integrity, and availability risk (GitHub Advisory, Feedly).

No public proof-of-concept exploit code has been identified, and there is no evidence of active in-the-wild exploitation as of the time of disclosure (Github Advisory). The EPSS score is approximately 0.019–0.022%, placing it in the 6th percentile for exploitation likelihood within 30 days. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. Exploitation requires a valid authenticated account with at least global:member role on the target n8n Community Edition instance, limiting the attack surface to insider threats or compromised accounts (GitHub Advisory).

1. Obtain access: Acquire or compromise a global:member account on a vulnerable n8n Community Edition instance (versions < 1.123.27, < 2.13.3, or = 2.14.0).
2. Enumerate credentials by name: Use the n8n API or UI to enumerate credential names visible on the instance. The name-based resolution path does not enforce ownership, so credential names belonging to other users may be discoverable.
3. Resolve target credential ID: Leverage the name-based credential resolution endpoint to obtain the internal credential ID of a target user's httpBasicAuth, httpHeaderAuth, or httpQueryAuth credential.
4. Craft a malicious workflow: Create a new workflow that references the resolved credential ID in an HTTP Request node or similar node that uses generic HTTP credential types.
5. Trigger workflow execution: Execute the crafted workflow. The credentials permission checker skips validation for generic HTTP credential types, so the pre-execution authorization check does not block the request.
6. Capture plaintext secrets: The workflow decrypts and uses the target credential during execution. The attacker can capture the plaintext secret via workflow output, logs, or an attacker-controlled HTTP endpoint configured as the workflow's target. (GitHub Advisory)

• Logs: n8n execution logs showing a global:member user executing workflows that reference credentials not owned by or shared with that user; unexpected workflow executions involving httpBasicAuth, httpHeaderAuth, or httpQueryAuth credential types.
• Logs: API access logs showing credential name resolution or credential ID lookup requests from member-role accounts for credentials belonging to other users or projects.
• Network: Outbound HTTP requests from n8n to attacker-controlled endpoints (e.g., webhook catchers, Burp Collaborator) carrying HTTP Basic Auth headers, custom headers, or query parameters containing credential values.
• Application Behavior: Workflows created by member-role users that reference credentials from other users' projects or namespaces, particularly those using generic HTTP credential types (httpBasicAuth, httpHeaderAuth, httpQueryAuth). (GitHub Advisory)

Upgrade n8n Community Edition to version 1.123.27 (v1 branch), 2.13.3, or 2.14.1 (v2 branch) or later, as these releases contain the fix (GitHub Advisory). If immediate upgrade is not possible, administrators should: (1) restrict instance access to fully trusted users only, and (2) audit and rotate all generic HTTP credentials (httpBasicAuth, httpHeaderAuth, httpQueryAuth) stored on the instance. Note that these workarounds do not fully remediate the risk. Enterprise Edition users are not affected due to additional permission gates on workflow creation and execution.

Heise Online covered the vulnerability as part of a broader report on critical vulnerabilities threatening the n8n automation platform, noting it alongside other significant security issues (Heise). The vulnerability was reported by security researcher tr4ce-ju and published by n8n maintainer Jubke via GitHub's security advisory process (GitHub Advisory). Beyond Machines also covered n8n's patch release addressing this and related vulnerabilities (Beyond Machines).