CVE-2026-42236

high

n8n is an open source workflow automation platform.

Vendor / product: N8n — n8n

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

7.5

7.5 (CVSS v3.1)

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

Severity source: NVD CVSS v3.1 (nvd@nist.gov)

Timeline (UTC)

Published: 2026-05-04 19:16

Modified: 2026-11-11 23:10

NVD status: Analyzed

Last synced 3 hours ago

Verified against the source API 2026-11-11 23:13 UTC

Exploitation

Not listed in CISA KEV (as of last catalog sync)

Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).

Affected products

n8n / n8n <1.123.32, ≥2.17.0 ≤2.17.4, 2.18.0

Weakness classification (CWE)

CWE-770

Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.

Mitigation & advisories

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

References

https://github.com/n8n-io/n8n/security/advisories/GHSA-49m9-pgww-9vq6 security-advisories@github.com

Data sources

NVD CVE API 2.0 — fetched 2026-11-11 23:13 UTC · record ↗

Learn the basics

Understanding CVEs and CVSS Scores

CVE-2026-42236

Affected products

Weakness classification (CWE)

Mitigation & advisories

References

Data sources

Learn the basics

Related CVEs