NVD / CVE Program· CNA GitHub_M

CVE-2026-54052: n8n-MCP: Cross-tenant access to workflow version backups in multi-tenant HTTP deployments

Noroxi assessment

Priority: Monitor (action score 39/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.38% (FIRST EPSS).
Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
Fixed version: czlonkowski n8n-mcp 2.56.1.

Low priority for now. Upgrade to czlonkowski n8n-mcp 2.56.1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

n8n-MCP is an MCP server that provides AI assistants access to n8n node documentation, properties, and operations. Prior to 2.56.1, in HTTP mode with multi-tenancy enabled through ENABLE_MULTI_TENANT=true, n8n-mcp's local workflow version history backups were not isolated per tenant, allowing an authenticated tenant to read workflow version snapshots belonging to other tenants and delete or destroy other tenants' stored backups, including full node definitions, credential references, and authorization headers. This issue is fixed in version 2.56.1.

CriticalCVSS 9.9 · v3.1—No exploit Fix available

Broken access control (IDOR)

GHSA-j6r7-6fhx-77wx

Published: Jul 15, 2026
Updated: Oct 24, 2026
EPSS: 0.3% · 33th percentile
CWE: CWE-639

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 39 / 40 · 9.9 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.3%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: 9.9
CNA · GitHub_M: 9.9; agree

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
n8n-mcp	n8n-mcp	cpe:2.3:a:n8n-mcp:n8n-mcp

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

n8n-mcp n8n-mcpbefore 2.56.1

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

czlonkowski n8n-mcp
- < 2.56.1affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
npm	n8n-mcp	before 2.56.1	2.56.1

Same product

n8n-mcp: all records

Other highest-scoring records for the same primary product.

CVE-2026-42449n8n-MCP: IPv4-mapped IPv6 addresses bypass SSRF protection in validateUrlSync(), enabling full SSRF for SDK embedders
34Monitor
CVE-2026-39974n8n-MCP has an Authenticated SSRF via instance-URL header in multi-tenant HTTP mode
34Monitor
CVE-2026-45707n8n-MCP: Multi-tenant MCP requests fall back to process-level n8n credentials when tenant headers are absent or incomplete
32Monitor

Published before and after this one in the same product

← EarlierCVE-2026-44694May 8, 2026 · n8n-MCP: Authenticated SSRF in n8n-mcp webhook and API client paths
28Monitor
← EarlierCVE-2026-45582May 29, 2026 · n8n-MCP: Workflow telemetry sanitizer could retain partial values from URL-shaped node parameters
26Monitor
Later →CVE-2026-55608Jul 15, 2026 · n8n-MCP: Incorrect authorization can expose default-scope workflow version backups in multi-tenant HTTP mode
21Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
czlonkowski n8n-mcp	2.56.1 · description	Vendor (CNA)
npm:n8n-mcp	2.56.1	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
A low-privileged account is enough.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: high · data can be read
Integrity: high · data or configuration can be modified
Availability: low · the service can be disrupted

Impact can extend beyond the vulnerable component (scope changes).

Attack vector: Network
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Changed
Confidentiality impact: High
Integrity impact: High
Availability impact: Low

Weakness class (CWE)

CWE-639 · Authorization Bypass Through User-Controlled Key

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L

nvd-primary

Root cause

The endpoint fetches the record by the ID sent in the request, but never checks whether the record belongs to the requesting user.

The bug in code

The whole CWE-639 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1const invoice = await Invoice.findById(req.params.id);
2res.json(invoice);

Fixed

1const invoice = await Invoice.findOne({
2  id: req.params.id,
3  ownerId: req.user.id,
4});
5if (!invoice) return res.sendStatus(404);
6res.json(invoice);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

Fix✗ → ✓Sep 28, 2026, 10:46 PM UTC

For records you follow, these changes also arrive as notifications. →

References

github.com/czlonkowski/n8n-mcp/releases/tag/v2.56.1

Show all references (1 more)

github.com/czlonkowski/n8n-mcp/security/advisories/GHSA-j6r7-6fhx-77wx

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records