| Package | Affected versions | Patched versions |
|---|---|---|
| n8n | = 2.18.0≥ 2.17.0, < 2.17.4< 1.123.32 | 2.17.41.123.32 |
| n8n | ≥ 2.17.0, < 2.17.4≥ 2.18.0, < 2.18.1< 1.123.32 | 2.17.42.18.11.123.32 |
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 fixed in n8n version 2.14.2. Users should upgrade to this version or later to remediate the vulnerability.
If upgrading is not immediately possible, administrators should consider the following temporary mitigations:
These workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.
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