CVE-2026-42236

n8n is an open source workflow automation platform. Prior to versions 1.123.32, 2.17.4, and 2.18.1, the MCP OAuth client registration endpoint accepted unauthenticated requests and stored client data without adequate resource controls. An unauthenticated remote attacker could exhaust server memory resources by sending large registration payloads, rendering the n8n instance unavailable. The MCP enable/disable toggle gates MCP access but did not restrict client registrations, meaning the endpoint is reachable regardless of whether MCP access is enabled on the instance. This issue has been patched in versions 1.123.32, 2.17.4, and 2.18.1.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/n8n-io/n8n/security/advisories/GHSA-49m9-pgww-9vq6	Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:n8n:n8n:::::enterprise:node.js::
	cpe:2.3:a:n8n:n8n:::::enterprise:node.js::
	cpe:2.3:a:n8n:n8n:2.18.0::::enterprise:node.js::*

History

06 May 2026, 17:16

Type	Values Removed	Values Added
First Time		N8n n8n N8n
CPE		cpe:2.3:a:n8n:n8n:2.18.0::::enterprise:node.js::* cpe:2.3:a:n8n:n8n:::::enterprise:node.js::
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 7.5
References	~~() https://github.com/n8n-io/n8n/security/advisories/GHSA-49m9-pgww-9vq6 -~~	() https://github.com/n8n-io/n8n/security/advisories/GHSA-49m9-pgww-9vq6 - Vendor Advisory

04 May 2026, 19:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-05-04 19:16

Updated : 2026-05-06 17:16

NVD link : CVE-2026-42236

Mitre link : CVE-2026-42236

CVE.ORG link : CVE-2026-42236

JSON object : View

Products Affected

n8n

n8n

CWE

CWE-770

Allocation of Resources Without Limits or Throttling

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