XSS in N8n

CVE-2026-42235

n8n is an open source workflow automation platform. Prior to versions 1.123.32, 2.17.4, and 2.18.1, an unauthenticated attacker could register a malicious MCP OAuth client with a crafted client_name. If a victim user authorized the OAuth consent dialog and a second user subsequently revoked that access, a toast notification would render the injected script. Clicking the link would execute arbitrary JavaScript in the victim's authenticated n8n browser session, enabling credential and session token theft, workflow manipulation, or privilege escalation. This issue has been patched in versions 1.123.32, 2.17.4, and 2.18.1.

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.003 (25.8th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.6 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H.

Affected products

  • N8n — versions 2.18.0
  • N8n-io N8n — versions < 1.123.32, >= 2.17.0, < 2.17.4, >= 2.18.0, < 2.18.1

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-42235?
CVE-2026-42235 is a critical-severity vulnerability in N8n, classified under Cross-site Scripting. CVSS score: 9.6/10. Published 2026-05-04.
How severe is CVE-2026-42235?
Critical severity. CVSS v3 base score is 9.6 out of 10.