Summary
n8n-MCP: Cross-tenant access to workflow version backups in multi-tenant HTTP deployments
Affected configurations
- HTTP mode with multi-tenancy enabled (
ENABLE_MULTI_TENANT=true), where multiple tenants are served by a single shared instance and database.
Not affected:
- stdio / single-user deployments (e.g. Claude Desktop).
- Single-tenant HTTP deployments (one tenant per instance and database).
Affected versions
<= 2.56.0
Patched version
2.56.1. The stored version history is now isolated per instance, so a tenant can only access its own backups. Upgrading runs a one-time migration that isolates existing history and clears previously stored, un-scoped backups (these are auto-created, short-retention backups).
Workarounds
If users cannot upgrade immediately:
- Disable the workflow version tool by setting
DISABLED_TOOLS=n8n_workflow_versionsin the server environment (for example, in your Docker.env). This removes the affected tool from the deployment for all tenants; automatic backups are unaffected, but the cross-tenant access path is closed. - Alternatively, do not run in multi-tenant mode, serve each tenant from a separate instance with its own database, so no local store is shared between tenants.
- Restrict network access to the HTTP endpoint to trusted operators.
stdio and single-tenant HTTP deployments are not affected.
Credit
Reported by Francisco Rosales (@0xmagic0) and coordinated by Ax Sharma (@axsharma) of Manifold Security.
Impact
In multi-tenant HTTP deployments, where a single n8n-mcp server serves several tenants, the locally stored workflow version history (the automatic backups taken before workflow updates) was not isolated per tenant. An authenticated tenant could read workflow version snapshots belonging to other tenants, and could delete or destroy other tenants' stored backups.
A stored snapshot includes full node definitions, so the exposed data can contain credential references and authorization headers configured on nodes. This is therefore a confidentiality issue in addition to an integrity/availability one.
The application does not perform an authorization check before performing a sensitive operation. Typical impact: unauthorized access to restricted functionality or data.
CVE-2026-54052 has a CVSS score of 9.9 (Critical). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2.56.1); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2026-54052? CVE-2026-54052 is a critical-severity missing authorization vulnerability in n8n-mcp (npm), affecting versions <= 2.56.0. It is fixed in 2.56.1. The application does not perform an authorization check before performing a sensitive operation.
- How severe is CVE-2026-54052? CVE-2026-54052 has a CVSS score of 9.9 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of n8n-mcp are affected by CVE-2026-54052? n8n-mcp (npm) versions <= 2.56.0 is affected.
- Is there a fix for CVE-2026-54052? Yes. CVE-2026-54052 is fixed in 2.56.1. Upgrade to this version or later.
- Is CVE-2026-54052 exploitable, and should I be worried? Whether CVE-2026-54052 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-54052 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-54052? Upgrade
n8n-mcpto 2.56.1 or later.