GHSA-3c7f-5hgj-h279 n8n has XSS in Chat Trigger Node through Custom CSS

• npm n8n: < 1.123.27 → fixed in 1.123.27 • npm n8n: >= 2.14.0, < 2.14.1 → fixed in 2.14.1 • npm n8n: >= 2.0.0-rc.0, < 2.13.3 → fixed in 2.13.3

Impact An authenticated user with permission to create or modify workflows could inject malicious JavaScript into the Custom CSS field of the Chat Trigger node. Due to a misconfiguration in the `sanitize-html` library, the sanitization could be bypassed, resulting in stored XSS on the public chat page. Any user visiting the chat URL would be affected. Patches The issue has been fixed in n8n versions 1.123.27, 2.13.3, and 2.14.1. Users should upgrade to one of these versions or later to remediate the vulnerability. Workarounds If upgrading is not immediately possible, administrators should consider the following temporary mitigations: • Limit workflow creation and editing permissions to fully trusted users only. • Disable the Chat Trigger node by adding `@n8n/n8n-nodes-langchain.chatTrigger` to the `NODES_EXCLUDE` environment variable. These workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.