MEDIUM CVSS 6.5
Published: 2026-04-20

CVE-2026-40896

openproject openproject Security Advisory (CVE-2026-40896)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-40896 impacting openproject openproject. Evaluated with CVSS Base Score of 6.5 (MEDIUM).

Original NVD Description

Source: NIST NVD
OpenProject is open-source, web-based project management software. Prior to version 17.3.0, a user with `manage_agendas` permission in any project can inject agenda items into meetings belonging to any other project on the instance — even projects they have no access to. No knowledge of the target project, meeting, or victim is required; the attacker can blindly spray items into every meeting on the instance by iterating sequential section IDs. Version 17.3.0 patches the issue.

📊 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
High (I:H)
Total modification of target system
Availability
None (A:N)
No system availability impact

🎯 Affected Versions Matrix

Affected Product openproject / openproject
Affected Versions *
Weakness Enumeration CWE-367

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-2026-40896 impacting openproject openproject.

⚡ Nuclei Detection Template (YAML) cve-2026-40896.yaml
id: cve-2026-40896

info:
  name: openproject openproject - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: medium
  description: |
    Automated signature & scanner for CVE-2026-40896 affecting openproject openproject.
    Evaluation: OpenProject is open-source, web-based project management software. Prior to version 17.3.0, a user with `manage_agendas` permission in any project can...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-40896
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
    cvss-score: 6.5
    cve-id: CVE-2026-40896
    cwe-id: CWE-367
  tags: cve,cve-2026-40896,openproject,openproject,medium

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "openproject"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-40896.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-40896
# Target: openproject openproject | 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-2026-40896 (openproject openproject)...")
    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 openproject openproject 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-2026-40896.sh
# Recommended Remediation & Patching Commands for CVE-2026-40896
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install openproject 2>/dev/null || \
sudo dnf upgrade openproject 2>/dev/null || \
sudo yum update openproject

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

# 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-2026-40896 in openproject openproject?

Review vendor-specific security notices and update openproject openproject 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-2026-40896?

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-2026-40896?

CVE-2026-40896 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-2026-40896
Weakness CWE-367
Vendor openproject
Product openproject
Published 2026-04-20
Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N