MEDIUM CVSS 6.5
Published: 2026-07-08

CVE-2026-35211

citeum opencti Security Advisory (CVE-2026-35211)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-35211 impacting citeum opencti. Evaluated with CVSS Base Score of 6.5 (MEDIUM).

Original NVD Description

Source: NIST NVD
OpenCTI is an open source platform for managing cyber threat intelligence knowledge and observables. Prior to 7.260401.0, the OpenCTI GraphQL API exposes a script filter operator in its FilterOperator enum that allows any authenticated user with the KNOWLEDGE capability to pass user-supplied Elasticsearch Painless script values directly into search queries without validation or sanitization, allowing computationally expensive scripts to consume cluster CPU resources and degrade or deny service for all users. This issue is fixed in version 7.260401.0.

📊 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
High (A:H)
Total denial of service or shutdown

🎯 Affected Versions Matrix

Affected Product citeum / opencti
Affected Versions *
Weakness Enumeration CWE-94

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-2026-35211 impacting citeum opencti.

⚡ Nuclei Detection Template (YAML) cve-2026-35211.yaml
id: cve-2026-35211

info:
  name: citeum opencti - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: medium
  description: |
    Automated signature & scanner for CVE-2026-35211 affecting citeum opencti.
    Evaluation: OpenCTI is an open source platform for managing cyber threat intelligence knowledge and observables. Prior to 7.260401.0, the OpenCTI GraphQL API expo...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-35211
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
    cvss-score: 6.5
    cve-id: CVE-2026-35211
    cwe-id: CWE-94
  tags: cve,cve-2026-35211,citeum,opencti,medium

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "opencti"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-35211.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-35211
# Target: citeum opencti | CVSS: 6.5 (MEDIUM)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-35211 (citeum opencti)...")
    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 citeum opencti 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-2026-35211.sh
# Recommended Remediation & Patching Commands for CVE-2026-35211
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install opencti 2>/dev/null || \
sudo dnf upgrade opencti 2>/dev/null || \
sudo yum update opencti

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

# 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.

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2026-35211 in citeum opencti?

Review vendor-specific security notices and update citeum opencti 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-2026-35211?

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-2026-35211?

CVE-2026-35211 is classified with a CVSS 3.1 Base Score of 6.5 (MEDIUM). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
6.5
MEDIUM SEVERITY
CVE ID CVE-2026-35211
Weakness CWE-94
Vendor citeum
Product opencti
Published 2026-07-08
Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H