CVE-2026-59206 in n8n
Summary
by MITRE • 07/09/2026
n8n is an open source workflow automation platform. Prior to 1.123.61, 2.27.4, and, 2.28.1, an authenticated user with the default workflow:create permission could pollute Object.prototype through a crafted workflow saved, updated, or imported via the workflow API, allowing unauthenticated requests to be treated as a privileged user and exposing user and project listing endpoints. This issue is fixed in versions 1.123.61, 2.27.4, and 2.28.1.
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Analysis
by VulDB Data Team • 07/09/2026
The vulnerability in n8n workflow automation platform represents a critical prototype pollution flaw that undermines the security model of the application. This issue affects versions prior to 1123.61, 227.4, and 228.1, where authenticated users with minimal workflow:create permissions can manipulate the Object.prototype through carefully crafted workflow data. The vulnerability stems from inadequate input sanitization during workflow import and save operations via the API endpoints. When a malicious user creates or modifies a workflow containing specially crafted payload data, the application fails to properly validate and sanitize the object structure before incorporating it into the prototype chain. This prototype pollution occurs during the deserialization process when workflow data is processed through the system's internal parsing mechanisms.
The operational impact of this vulnerability extends beyond simple privilege escalation as it creates a fundamental breakdown in the application's access control model. An attacker who successfully pollutes Object.prototype can manipulate how the system interprets user authentication states, effectively allowing unauthenticated requests to be treated as if they were authenticated with elevated privileges. This compromise affects core endpoints that list users and projects within the n8n environment, potentially exposing sensitive information about system users, their permissions, and project structures. The vulnerability particularly impacts organizations relying on n8n for workflow automation, as it undermines the trust boundary between authenticated and unauthenticated users. Attackers can leverage this flaw to gain unauthorized access to user data and project configurations that should only be accessible to authorized personnel.
This security weakness aligns with CWE-471, which specifically addresses the vulnerability of objects being modified in an unexpected way through prototype pollution attacks, and can be mapped to ATT&CK technique T1078.101 for valid accounts and T1566.002 for spearphishing attachments, as the initial compromise often occurs through workflow imports that may contain malicious payloads. The vulnerability demonstrates poor input validation practices in the API layer where user-supplied data should be strictly validated against expected object structures before being processed. Organizations using n8n are advised to immediately upgrade to versions 1123.61, 227.4, or 228.1 to address this issue. Additional mitigations include implementing stricter API rate limiting for workflow operations and monitoring for unusual workflow import patterns that might indicate prototype pollution attempts. The fix involves enhanced input sanitization routines that prevent object property modifications during workflow processing and implement proper deep cloning of workflow data structures to avoid prototype chain contamination.