CVE-2026-103252 is an authorization bypass vulnerability in n8n's credential test endpoint affecting versions <1.123.80, >=2.0.0 <2.39.6, and >=2.40.0 <2.40.1. The vulnerability arises because the endpoint resolves project-scoped variables without verifying if the caller has access rights to the specified project. Attackers can exploit this by specifying arbitrary project IDs in requests, causing sensitive variables to be interpolated and sent to attacker-controlled hosts, potentially leaking confidential information.

An attacker with limited privileges can bypass authorization controls to access sensitive project-scoped variables. This can result in unauthorized disclosure of sensitive credentials or configuration data by exfiltrating them to attacker-controlled endpoints. The vulnerability has a CVSS 4.0 base score of 7.1, indicating high severity due to network attack vector, low attack complexity, and high impact on confidentiality.

Users should upgrade n8n to versions 1.123.80 or later, 2.39.6 or later, or 2.40.1 or later where this vulnerability is fixed. Since this is a software vulnerability with fixed versions available, applying the official patches is the recommended remediation. No vendor advisory content was provided to indicate otherwise.