| Component | n8n |
| Severity | high (CVSS 7.5) |
| CVSS vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| Published (NVD) | 2026-05-04 |
| Last modified | 2026-06-17 |
| Affected versions | n8n < 1.123.32 n8n >= 2.17.0, <= 2.17.4 n8n = 2.18.0 |
| Fixed in | 1.123.32 |
| Weakness | CWE-770 |
| CISA KEV | not listed |
NVD description
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.
What to do
- Upgrade n8n to
1.123.32or later. - Do not expose the component's API or UI to the internet without authentication in front of it.
Sources
Read more
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