CVE-2026-110847 in n8n
Summary
by MITRE • 10/15/2026
n8n before 1.123.83, 2.x before 2.41.4, and 2.42.x before 2.42.1 contains a stored cross-site scripting vulnerability in the Chat Trigger hosted-chat page, where insufficiently sanitised customCss values are interpolated into the page as markup. Workflow authors can publish a chat without n8n user authentication whose payload executes on the instance origin, acting on the sessions of signed-in visitors.
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Analysis
by VulDB Data Team • 10/15/2026
The identified vulnerability represents a critical security flaw within the n8n automation platform, specifically affecting versions prior to 1.123.83, all 2.x releases before 2.41.4, and 2.42.x releases preceding version 2.42.1. This issue is classified as a stored cross-site scripting vulnerability located within the Chat Trigger hosted-chat page component. The root cause of this flaw lies in the insufficient sanitization of custom CSS values that are directly interpolated into the HTML markup without adequate validation or encoding. When an attacker crafts and publishes a workflow containing malicious script payloads embedded within these custom CSS fields, the n8n instance fails to strip or escape dangerous characters such as angle brackets or event handlers before rendering them in the browser context of visitors accessing the hosted chat interface.
From an operational perspective, this vulnerability allows for persistent code execution on the client side because the payload is stored server-side and served to every user who visits the specific chat page associated with that workflow. The impact is particularly severe due to the potential lack of authentication requirements for certain published workflows. If a workflow author configures their chat trigger to be publicly accessible without requiring n8n user authentication, any visitor to that page will inadvertently execute the attacker's JavaScript code within the security context of the n8n instance origin. This enables the malicious script to act on behalf of signed-in visitors who may have active sessions with administrative privileges or access to sensitive automation workflows and data sources connected through the platform.
The exploitation of this vulnerability aligns closely with Common Weakness Enumeration standard CWE-79, which describes Improper Neutralization of Input During Web Page Generation commonly known as Cross-site Scripting. Furthermore, in terms of tactical classification under the MITRE ATT&CK framework for enterprise security, this behavior corresponds to techniques involving Client-Side Injection and potentially Account Manipulation if the attacker leverages the victim's session cookies or tokens to perform unauthorized actions within the n8n environment. The persistence aspect inherent in stored XSS means that remediation is not limited to a single user interaction but affects all subsequent visitors until the malicious workflow is removed or patched, thereby amplifying the blast radius of the compromise significantly compared to reflected variants.
To mitigate this risk, organizations running affected versions of n8n must immediately upgrade to version 1.123.83 or later for the legacy branch, version 2.41.4 or later for the older major release line, and specifically version 2.42.1 or higher for the current 2.42.x series. These updates contain necessary input validation logic that properly sanitizes custom CSS inputs before they are rendered in the DOM. Additionally, administrators should review their workflow configurations to ensure that chat triggers requiring sensitive operations enforce strict authentication policies rather than remaining publicly accessible without verification. Implementing a Content Security Policy header can also provide an additional layer of defense by restricting the sources from which scripts can be executed, thereby limiting the impact even if similar vulnerabilities are discovered in future releases.