MEDIUM CVSS 4.3
Published: 2026-07-10

CVE-2026-58661

n8n n8n Security Advisory (CVE-2026-58661)
↗ Official NIST NVD Record
Seeking technical exploit breakdowns or verified PoC code for CVE-2026-58661?
🔬 Search Writeups & Exploit Archive →

CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-58661 impacting n8n n8n. Evaluated with CVSS Base Score of 4.3 (MEDIUM).

Original NVD Description

Source: NIST NVD
n8n before 2.28.0 (and before 1.123.58 on the 1.x branch) contains a disk space exhaustion vulnerability in the data-table file upload endpoint. The per-request quota check does not account for files already written to the shared temporary directory, allowing an authenticated user to repeatedly upload files that accumulate on disk until the periodic cleanup runs, potentially exhausting available disk space on the host.

📊 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
None (UI:N)
Zero human interaction required
Scope
Unchanged (S:U)
Confined to same security context
Confidentiality
None (C:N)
No data confidentiality impact
Integrity
None (I:N)
No system modification impact
Availability
Low (A:L)
Partial service performance degradation

🎯 Affected Versions Matrix

Affected Product n8n / n8n
Affected Versions *
Weakness Enumeration CWE-770

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-2026-58661 impacting n8n n8n.

⚡ Nuclei Detection Template (YAML) cve-2026-58661.yaml
id: cve-2026-58661

info:
  name: n8n n8n - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: medium
  description: |
    Automated signature & scanner for CVE-2026-58661 affecting n8n n8n.
    Evaluation: n8n before 2.28.0 (and before 1.123.58 on the 1.x branch) contains a disk space exhaustion vulnerability in the data-table file upload endpoint. The p...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-58661
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
    cvss-score: 4.3
    cve-id: CVE-2026-58661
    cwe-id: CWE-770
  tags: cve,cve-2026-58661,n8n,n8n,medium

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-2026-58661.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-58661
# Target: n8n n8n | CVSS: 4.3 (MEDIUM)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-58661 (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-2026-58661.sh
# Recommended Remediation & Patching Commands for CVE-2026-58661
# 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-2026-58661 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-2026-58661?

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-2026-58661?

CVE-2026-58661 is classified with a CVSS 3.1 Base Score of 4.3 (MEDIUM). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
4.3
MEDIUM SEVERITY
CVE ID CVE-2026-58661
Weakness CWE-770
Vendor n8n
Product n8n
Published 2026-07-10
Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L