CVE-2026-54052: Cross-Tenant Workflow Backup Access in n8n-MCP Exposes Embedded Credentials

What the Vulnerability Is

CVE-2026-54052 is an authorization bypass (CWE-639: Authorization Bypass Through User-Controlled Key, and CWE-862: Missing Authorization) affecting multi-tenant HTTP deployments of n8n-mcp. The root cause is insufficient validation of tenant and workflow identifiers on backup retrieval endpoints. By manipulating these identifiers in a request, an authenticated attacker in one tenant can retrieve stored workflow version backups belonging to a different tenant. Because n8n workflows frequently embed credentials, API keys, and webhook secrets directly in node configurations, successful exploitation can result in significant secondary compromise well beyond the initial application.

Affected Software

• Vendor/Package: npm
• Product: n8n-mcp
• Affected versions: <= 2.56.0
• CVSS: 9.9 (Critical)

No patched version has been published as of this writing.

Exploitation Status

A public proof-of-concept exists for this vulnerability (poc-public). This is not yet confirmed as weaponized in the wild or added to CISA's Known Exploited Vulnerabilities catalog, but public PoC availability substantially lowers the barrier to exploitation and typically precedes broader adoption by opportunistic attackers. Defenders running multi-tenant n8n-mcp deployments should treat this as an active, near-term risk rather than a theoretical one, particularly given the lack of an available patch.

How Our Detection Catches It

This detection ships across seven SIEM platforms: Microsoft Sentinel (KQL), Splunk (SPL), Elastic (EQL), IBM QRadar (AQL), Sumo Logic, Google Chronicle (YARA-L), and CrowdStrike (CQL).

At a high level, the logic focuses on identifying backup-retrieval requests where the tenant or workflow identifier referenced in the request does not align with the identifier associated with the requesting session or authentication context. Analysts should expect the underlying queries to correlate API/application logs against session-to-tenant mappings, surfacing requests where a caller's authenticated tenant scope diverges from the tenant scope of the workflow backup being accessed — a strong signal of cross-tenant enumeration or exploitation attempts.

Full Detection Details

For the complete detection logic, platform-specific queries, and response guidance, see the CVE-2026-54052 detection page.