n8n is a popular open-source tool for automating workflows. Recently, a security flaw was discovered in n8n that could allow attackers to inject malicious code. This vulnerability, identified as CVE-2026-56356, affects the Chat Trigger node and is rated as medium severity. It’s important for users to understand this risk and take the necessary steps to protect their systems.
This security issue involves a “stored Cross-Site Scripting” (XSS) vulnerability. In simple terms, this means that an attacker could save harmful code within n8n. If another user then views the affected part of n8n (specifically, a public chat page), this malicious code would run in their web browser without their knowledge, potentially leading to unauthorized actions or data theft. The vulnerability stems from a misconfiguration in how n8n cleans up user-provided input in the Chat Trigger node’s Custom CSS field.
CVE Details
- Product: n8n
- CVE ID: CVE-2026-56356
- Published: June 30, 2026
- Severity: Medium
- Status: Analyzed
Affected Products
The vulnerability impacts several versions of n8n:
- All versions before 1.123.27
- Versions 2.0.0 through 2.13.2
- Version 2.14.0
Current Status
This vulnerability has been analyzed and publicly disclosed. Patches are available to fix the issue.
Severity Level
The Common Vulnerability Scoring System (CVSS) rates this vulnerability with a base score of 5.4, classifying it as Medium severity. A medium severity rating indicates that while an attack requires some specific conditions (like an authenticated user with certain permissions), a successful exploitation could still lead to a noticeable impact, such as unauthorized access to data or control over the affected user’s session.
Possible Solutions
To protect your n8n instances from this stored XSS vulnerability, it is crucial to update to a patched version immediately. The following versions include the necessary fixes:
- 1.123.27 or later
- 2.13.3 or later
- 2.14.1 or later
If an immediate upgrade is not feasible, temporary mitigation steps can reduce the risk:
- Restrict Permissions: Limit the ability to create or modify workflows to only fully trusted users within your n8n environment. This reduces the number of individuals who could potentially exploit the vulnerability.
- Disable Chat Trigger Node: You can disable the problematic Chat Trigger node by adding
@n8n/n8n-nodes-langchain.chatTriggerto theNODES_EXCLUDEenvironment variable.
Please remember that these workarounds are temporary and do not fully eliminate the risk. A full update is the most effective solution.
References
https://github.com/n8n-io/n8n/security/advisories/GHSA-3c7f-5hgj-h279
https://www.vulncheck.com/advisories/n8n-stored-cross-site-scripting-in-chat-trigger-node-custom-css-field
