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CVE-2026-33749

MEDIUM

n8n Vulnerable to XSS via Binary Data Inline HTML Rendering

Published March 26, 2026Updated March 26, 2026Source: osv

Summary

## Impact An authenticated user with permission to create or modify workflows could craft a workflow that produces an HTML binary data object without a filename. The `/rest/binary-data` endpoint served such responses inline on the n8n origin without `Content-Disposition` or `Content-Security-Policy` headers, allowing the HTML to render in the browser with full same-origin JavaScript access. By sending the resulting URL to a higher-privileged user, an attacker could execute JavaScript in the victim's authenticated session, enabling exfiltration of workflows and credentials, modification of workflows, or privilege escalation to admin. ## 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. - Restrict network access to the n8n instance to prevent untrusted users from accessing binary data URLs. These workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.

Remediation

Upgrade to the fixed version using your package manager.

npm
Update n8n to 2.14.1 or later
npm install n8n@2.14.1
npm
Update n8n to 2.13.3 or later
npm install n8n@2.13.3
npm
Update n8n to 1.123.27 or later
npm install n8n@1.123.27

After upgrading, run your dependency scanner again to confirm the vulnerability is resolved.

Affected Packages (3)

PackageEcosystemAffectedFixed In
n8n
npm
2.14.02.14.1
n8n
npm
All versions2.13.3
n8n
npm
All versions1.123.27

Vulnerability Classification

Common Weakness Enumeration (CWE) identifiers for this vulnerability type.

  • CWE-79
    Cross-site Scripting (XSS)MITRE

CVSS Score Breakdown

What the CVSS (Common Vulnerability Scoring System) 8.9 score means for each attack dimension.

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
Required
Scope
Changed
Confidentiality
High
Integrity
High
Availability
Low

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:L

Frequently Asked Questions

What is CVE-2026-33749?
n8n Vulnerable to XSS via Binary Data Inline HTML Rendering This vulnerability has been assigned a severity rating of MEDIUM (CVSS score: 8.9/10).
How do I check if my project is affected by CVE-2026-33749?
CVE-2026-33749 affects n8n. Use GeekWala's free vulnerability scanner to check your dependencies against CVE-2026-33749 and 200,000+ other known vulnerabilities.

Severity & Exploitability

CVSS Score
8.9

High exploitability or significant impact. Prioritize remediation within days.

Also Known As

GHSA-qfc3-hm4j-7q77

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