Description
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.
Problem types
CWE-87: Improper Neutralization of Alternate XSS Syntax
CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Product status
>= 2.17.0, < 2.17.4
>= 2.18.0, < 2.18.1
References
github.com/...io/n8n/security/advisories/GHSA-537j-gqpc-p7fq