What is CVE-2026-54309?

CVE-2026-54309 is a critical-severity vulnerability in N8n, classified under Missing Authentication for Critical Function. CVSS score: 10.0/10. Published 2026-06-23.

How severe is CVE-2026-54309?

Critical severity. CVSS v3 base score is 10.0 out of 10.

Auth bypass in N8n

CVE-2026-54309

n8n is an open source workflow automation platform. Prior to 2.25.7 and 2.26.2, when @n8n/mcp-browser is run in HTTP transport mode, the MCP endpoint accepts session initialization and tool invocation requests without any authentication. A…

Vulnerability class: Broken Authentication

EPSS: 0.004 (33.1th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 10.0 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L.

Affected products

N8n
N8n-io N8n — versions >= 2.26.0, < 2.26.2, < 2.25.7

Weakness classification (CWE)

CWE-306 — Missing Authentication for Critical Function

References

security-advisories@github.com (x_refsource_CONFIRM, Mitigation, Vendor Advisory)

Frequently asked questions

What is CVE-2026-54309?: CVE-2026-54309 is a critical-severity vulnerability in N8n, classified under Missing Authentication for Critical Function. CVSS score: 10.0/10. Published 2026-06-23.
How severe is CVE-2026-54309?: Critical severity. CVSS v3 base score is 10.0 out of 10.