🛡️ CVE-2026-55608 — n8n-mcp

🟡 CVSS 4.2 — Medium ✅ No Known Exploit CWE-200 OSV
4.2
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

n8n-MCP: Incorrect authorization can expose default-scope workflow version backups in multi-tenant HTTP mode

Summary

In multi-tenant HTTP mode (ENABLE_MULTI_TENANT=true), an authenticated tenant could, under certain conditions, reach n8n-mcp's local default-scope workflow_versions backups instead of being confined to its own tenant scope. This affects n8n-mcp's own local workflow-version storage, not a normal n8n API capability.

Impact

An authenticated MCP HTTP tenant could read or delete workflow-version backups stored in the default (single-tenant) scope — for example backups left from a prior single-tenant deployment or a migration period. Workflow snapshots may contain sensitive workflow configuration depending on their contents. Single-tenant and stdio deployments are not affected.

Affected versions

<= 2.57.3

Patched version

2.57.4

Remediation

Upgrade to n8n-mcp 2.57.4 or later. The fix requires a complete tenant context in multi-tenant mode and fails closed for workflow-version access that cannot be attributed to a specific tenant.

Workarounds

  • Restrict network access to the HTTP endpoint (firewall / reverse proxy / VPN) so only trusted callers can reach it.
  • Run in stdio mode, which has no multi-tenant HTTP surface.
  • If default-scope backups from a prior single-tenant deployment are not needed, removing them eliminates the exposure.

Credit

Reported by @DavidCarliez.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is high, an attacker needs low-level privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality low, integrity low, availability none.

Weakness class

CVE-2026-55608 is classified as CWE-200: Exposure of Sensitive Information. Information that should stay internal is disclosed to someone who is not authorised to see it.

Affected software

CVE-2026-55608 is recorded against 1 package.

  • n8n-mcp

Timeline and source

Published on 14 July 2026 and last revised on 17 July 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from OSV.

References

github.com (Web)
github.com (Web)
github.com (Package)
github.com (Web)

Details

Severity MEDIUM
CVSS Score 4.2
CVSS Vector CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N
CWE CWE-200
Public Exploit ✅ No
Source OSV
Published 2026-07-14
Updated 2026-08-12
Modified 2026-07-17

Affected Packages

Software From version Fixed in
n8n-mcp — —

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