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Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CVE-2026-42235

High
8.8/10

Summary

n8n is an open source workflow automation platform. In versions prior to 1.123.32, 2.17.0 prior to 2.17.4, and 2.18.0, 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.

  • LOW
  • NETWORK
  • HIGH
  • CHANGED
  • REQUIRED
  • NONE
  • HIGH
  • HIGH

CWE-79 - Cross Site Scripting

Cross-Site Scripting, commonly referred to as XSS, is the most dominant class of vulnerabilities. It allows an attacker to inject malicious code into a pregnable web application and victimize its users. The exploitation of such a weakness can cause severe issues such as account takeover, and sensitive data exfiltration. Because of the prevalence of XSS vulnerabilities and their high rate of exploitation, it has remained in the OWASP top 10 vulnerabilities for years.

References

Advisory Timeline

  • Published