CRITICAL CVSS 9.6
Published: 2026-03-27

CVE-2026-33757

openbao openbao Security Advisory (CVE-2026-33757)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-33757 impacting openbao openbao. Evaluated with CVSS Base Score of 9.6 (CRITICAL).

Original NVD Description

Source: NIST NVD
OpenBao is an open source identity-based secrets management system. Prior to version 2.5.2, OpenBao does not prompt for user confirmation when logging in via JWT/OIDC and a role with `callback_mode` set to `direct`. This allows an attacker to start an authentication request and perform "remote phishing" by having the victim visit the URL and automatically log-in to the session of the attacker. Despite being based on the authorization code flow, the `direct` mode calls back directly to the API and allows an attacker to poll for an OpenBao token until it is issued. Version 2.5.2 includes an additional confirmation screen for `direct` type logins that requires manual user interaction in order to finish the authentication. This issue can be worked around either by removing any roles with `callback_mode=direct` or enforcing confirmation for every session on the token issuer side for the Client ID used by OpenBao.

📊 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
None (PR:N)
Unauthenticated execution
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
Low (A:L)
Partial service performance degradation

🎯 Affected Versions Matrix

Affected Product openbao / openbao
Affected Versions *
Weakness Enumeration CWE-384

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-2026-33757 impacting openbao openbao.

⚡ Nuclei Detection Template (YAML) cve-2026-33757.yaml
id: cve-2026-33757

info:
  name: openbao openbao - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: critical
  description: |
    Automated signature & scanner for CVE-2026-33757 affecting openbao openbao.
    Evaluation: OpenBao is an open source identity-based secrets management system. Prior to version 2.5.2, OpenBao does not prompt for user confirmation when logging...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-33757
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:L
    cvss-score: 9.6
    cve-id: CVE-2026-33757
    cwe-id: CWE-384
  tags: cve,cve-2026-33757,openbao,openbao,critical

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "openbao"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-33757.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-33757
# Target: openbao openbao | CVSS: 9.6 (CRITICAL)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-33757 (openbao openbao)...")
    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 openbao openbao 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-2026-33757.sh
# Recommended Remediation & Patching Commands for CVE-2026-33757
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install openbao 2>/dev/null || \
sudo dnf upgrade openbao 2>/dev/null || \
sudo yum update openbao

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

# 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-2026-33757 in openbao openbao?

Review vendor-specific security notices and update openbao openbao 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-2026-33757?

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-2026-33757?

CVE-2026-33757 is classified with a CVSS 3.1 Base Score of 9.6 (CRITICAL). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
9.6
CRITICAL SEVERITY
CVE ID CVE-2026-33757
Weakness CWE-384
Vendor openbao
Product openbao
Published 2026-03-27
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:L