CRITICAL CVSS 9.9
Published: 2026-03-10

CVE-2026-30921

hackerbay oneuptime Security Advisory (CVE-2026-30921)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-30921 impacting hackerbay oneuptime. Evaluated with CVSS Base Score of 9.9 (CRITICAL).

Original NVD Description

Source: NIST NVD
OneUptime is a solution for monitoring and managing online services. Prior to 10.0.20, OneUptime Synthetic Monitors allow low-privileged project users to submit custom Playwright code that is executed on the oneuptime-probe service. In the current implementation, this untrusted code is run inside Node's vm and is given live host Playwright objects such as browser and page. This creates a distinct server-side RCE primitive: the attacker does not need the classic this.constructor.constructor(...) sandbox escape. Instead, the attacker can directly use the injected Playwright browser object to reach browser.browserType().launch(...) and spawn an arbitrary executable on the probe host/container. This vulnerability is fixed in 10.0.20.

📊 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
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 hackerbay / oneuptime
Affected Versions *
Weakness Enumeration CWE-749

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-2026-30921 impacting hackerbay oneuptime.

⚡ Nuclei Detection Template (YAML) cve-2026-30921.yaml
id: cve-2026-30921

info:
  name: hackerbay oneuptime - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: critical
  description: |
    Automated signature & scanner for CVE-2026-30921 affecting hackerbay oneuptime.
    Evaluation: OneUptime is a solution for monitoring and managing online services. Prior to 10.0.20, OneUptime Synthetic Monitors allow low-privileged project users...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-30921
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
    cvss-score: 9.9
    cve-id: CVE-2026-30921
    cwe-id: CWE-749
  tags: cve,cve-2026-30921,hackerbay,oneuptime,critical

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "oneuptime"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-30921.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-30921
# Target: hackerbay oneuptime | CVSS: 9.9 (CRITICAL)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-30921 (hackerbay oneuptime)...")
    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 hackerbay oneuptime 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-2026-30921.sh
# Recommended Remediation & Patching Commands for CVE-2026-30921
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install oneuptime 2>/dev/null || \
sudo dnf upgrade oneuptime 2>/dev/null || \
sudo yum update oneuptime

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

# 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-2026-30921 in hackerbay oneuptime?

Review vendor-specific security notices and update hackerbay oneuptime 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-2026-30921?

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-2026-30921?

CVE-2026-30921 is classified with a CVSS 3.1 Base Score of 9.9 (CRITICAL). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
9.9
CRITICAL SEVERITY
CVE ID CVE-2026-30921
Weakness CWE-749
Vendor hackerbay
Product oneuptime
Published 2026-03-10
Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H