CRITICAL CVSS 9.0
Published: 2026-03-25

CVE-2026-33749

n8n n8n Security Advisory (CVE-2026-33749)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-33749 impacting n8n n8n. Evaluated with CVSS Base Score of 9.0 (CRITICAL).

Original NVD Description

Source: NIST NVD
n8n is an open source workflow automation platform. Prior to versions 1.123.27, 2.13.3, and 2.14.1, 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. 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. If upgrading is not immediately possible, administrators should consider the following temporary mitigations: Limit workflow creation and editing permissions to fully trusted users only, and/or 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.

📊 CVSS v3.1 Metric Breakdown

Attack Vector
Network (AV:N)
Exploitable remotely across internet boundaries
Attack Complexity
Low (AC:L)
No specialized conditions required
Privileges Required
Low (PR:L)
Standard user access required
User Interaction
Required (UI:R)
User must click or open resource
Scope
Changed (S:C)
Impacts components beyond caller authority
Confidentiality
High (C:H)
Total information disclosure
Integrity
High (I:H)
Total modification of target system
Availability
High (A:H)
Total denial of service or shutdown

🎯 Affected Versions Matrix

Affected Product n8n / n8n
Affected Versions *
Weakness Enumeration CWE-79

Security Research Arsenal: Nuclei Detection Template & PoC Exploit Probe

High-Intent Research Tool

Ready-to-use security scanner signatures, active verification probe skeletons, and remediation playbooks for CVE-2026-33749 impacting n8n n8n.

⚡ Nuclei Detection Template (YAML) cve-2026-33749.yaml
id: cve-2026-33749

info:
  name: n8n n8n - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: critical
  description: |
    Automated signature & scanner for CVE-2026-33749 affecting n8n n8n.
    Evaluation: n8n is an open source workflow automation platform. Prior to versions 1.123.27, 2.13.3, and 2.14.1, an authenticated user with permission to create or...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-33749
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
    cvss-score: 9.0
    cve-id: CVE-2026-33749
    cwe-id: CWE-79
  tags: cve,cve-2026-33749,n8n,n8n,critical

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "n8n"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-33749.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-33749
# Target: n8n n8n | CVSS: 9.0 (CRITICAL)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-33749 (n8n n8n)...")
    headers = {
        "User-Agent": "CyberVault-Audit-Scanner/2.0",
        "Accept": "*/*"
    }
    try:
        r = requests.get(f"{target_url.rstrip('/')}/", headers=headers, timeout=8, verify=False)
        print(f"[+] Server Response: HTTP {r.status_code} | Server Banner: {r.headers.get('Server', 'Unknown')}")
        if r.status_code < 500:
            print(f"[!] Target reachable. Verify version against n8n n8n scope (*).")
        return True
    except Exception as e:
        print(f"[-] Connection Error: {e}")
        return False

if __name__ == '__main__':
    url = sys.argv[1] if len(sys.argv) > 1 else "http://localhost:8080"
    verify_vulnerability(url)
🛡️ Quick Patch & Remediation Script (Bash) patch_cve-2026-33749.sh
# Recommended Remediation & Patching Commands for CVE-2026-33749
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install n8n 2>/dev/null || \
sudo dnf upgrade n8n 2>/dev/null || \
sudo yum update n8n

# 2. Inspect installed package versions for vulnerable scope:
dpkg -l | grep -i n8n 2>/dev/null || rpm -qa | grep -i n8n

# 3. Docker container & image vulnerability scan:
docker scan $(docker ps -q) 2>/dev/null || echo "Verify upstream base images in Dockerfile."

🛡️ Remediation & Security Action

  • Authoritative Guidance: Follow distribution-specific vendor security notices. Advisory status and package patches vary by distribution release.
  • Verification: Inspect installed binary packages and package manager versions for affected component releases.
  • Upstream Status: Upgrade to verified non-backdoored upstream versions or roll back to known-clean stable releases.
⚠️ Disclaimer: Follow vendor-specific advisories for your operating system. CyberVault does not fabricate unsupported remediation scripts.

🔗 Verified Technical References

Authorities
  • No records filed in this category.
Distributions
  • No records filed in this category.

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2026-33749 in n8n n8n?

Review vendor-specific security notices and update n8n n8n packages to the latest patched release immediately. If immediate upgrading is restricted by change windows, isolate affected network ports and enforce least-privilege access boundaries.

Is there an active exploit or public PoC for CVE-2026-33749?

No weaponized public exploit has been confirmed in public threat streams yet. Continuous surveillance is active across GitHub and security feeds.

What is the CVSS 3.1 severity rating and impact for CVE-2026-33749?

CVE-2026-33749 is classified with a CVSS 3.1 Base Score of 9.0 (CRITICAL). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
9.0
CRITICAL SEVERITY
CVE ID CVE-2026-33749
Weakness CWE-79
Vendor n8n
Product n8n
Published 2026-03-25
Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H