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CVE-2026-42235

n8n: XSS via MCP OAuth client PUBLISHED

Description (CNA)

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.

Affected (CNA)

Vendor / productVersions
n8n-io / n8naffected < 1.123.32; affected >= 2.17.0, < 2.17.4; affected >= 2.18.0, < 2.18.1

CWE

CWE-87, CWE-79

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.