MEDIUM CVSS 6.5
Published: 2021-04-01

CVE-2021-26581

hpe superdome_flex_server_firmware Security Advisory (CVE-2021-26581)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2021-26581 impacting hpe superdome_flex_server_firmware. Evaluated with CVSS Base Score of 6.5 (MEDIUM).

Original NVD Description

Source: NIST NVD
A potential security vulnerability has been identified in HPE Superdome Flex server. A denial of service attack can be remotely exploited leaving hung connections to the BMC web interface. The monarch BMC must be rebooted to recover from this situation. Other BMC management is not impacted. HPE has made the following software update to resolve the vulnerability in HPE Superdome Flex Server: Superdome Flex Server Firmware 3.30.142 or later.

📊 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 hpe / superdome_flex_server_firmware
Affected Versions *
Weakness Enumeration NVD-CWE-noinfo

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-2021-26581 impacting hpe superdome_flex_server_firmware.

⚡ Nuclei Detection Template (YAML) cve-2021-26581.yaml
id: cve-2021-26581

info:
  name: hpe superdome_flex_server_firmware - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: medium
  description: |
    Automated signature & scanner for CVE-2021-26581 affecting hpe superdome_flex_server_firmware.
    Evaluation: A potential security vulnerability has been identified in HPE Superdome Flex server. A denial of service attack can be remotely exploited leaving hung...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2021-26581
  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-2021-26581
    cwe-id: NVD-CWE-noinfo
  tags: cve,cve-2021-26581,hpe,superdome_flex_server_fir,medium

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "superdome_flex_server_firmware"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2021-26581.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2021-26581
# Target: hpe superdome_flex_server_firmware | 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-2021-26581 (hpe superdome_flex_server_firmware)...")
    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 hpe superdome_flex_server_firmware 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-2021-26581.sh
# Recommended Remediation & Patching Commands for CVE-2021-26581
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install superdome_flex_server_fir 2>/dev/null || \
sudo dnf upgrade superdome_flex_server_fir 2>/dev/null || \
sudo yum update superdome_flex_server_fir

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

# 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

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2021-26581 in hpe superdome_flex_server_firmware?

Review vendor-specific security notices and update hpe superdome_flex_server_firmware 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-2021-26581?

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-2021-26581?

CVE-2021-26581 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-2021-26581
Weakness NVD-CWE-noinfo
Vendor hpe
Product superdome_flex_server_firmware
Published 2021-04-01
Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H