HIGH CVSS 7.8
Published: 2026-03-24

CVE-2026-27784

f5 nginx_open_source Security Advisory (CVE-2026-27784)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-27784 impacting f5 nginx_open_source. Evaluated with CVSS Base Score of 7.8 (HIGH).

Original NVD Description

Source: NIST NVD
The 32-bit implementation of NGINX Open Source has a vulnerability in the ngx_http_mp4_module module, which might allow an attacker to over-read or over-write NGINX worker memory resulting in its termination, using a specially crafted MP4 file. The issue only affects 32-bit NGINX Open Source if it is built with the ngx_http_mp4_module module and the mp4 directive is used in the configuration file. Additionally, the attack is possible only if an attacker can trigger the processing of a specially crafted MP4 file with the ngx_http_mp4_module module. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

📊 CVSS v3.1 Metric Breakdown

Attack Vector
Local (AV:L)
Requires local system execution permissions
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
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 f5 / nginx_open_source
Affected Versions *
Weakness Enumeration CWE-190

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-2026-27784 impacting f5 nginx_open_source.

⚡ Nuclei Detection Template (YAML) cve-2026-27784.yaml
id: cve-2026-27784

info:
  name: f5 nginx_open_source - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: high
  description: |
    Automated signature & scanner for CVE-2026-27784 affecting f5 nginx_open_source.
    Evaluation: The 32-bit implementation of NGINX Open Source has a vulnerability in the ngx_http_mp4_module module, which might allow an attacker to over-read or ov...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-27784
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 7.8
    cve-id: CVE-2026-27784
    cwe-id: CWE-190
  tags: cve,cve-2026-27784,f5,nginx_open_source,high

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "nginx_open_source"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-27784.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-27784
# Target: f5 nginx_open_source | CVSS: 7.8 (HIGH)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-27784 (f5 nginx_open_source)...")
    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 f5 nginx_open_source 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-2026-27784.sh
# Recommended Remediation & Patching Commands for CVE-2026-27784
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install nginx_open_source 2>/dev/null || \
sudo dnf upgrade nginx_open_source 2>/dev/null || \
sudo yum update nginx_open_source

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

# 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-2026-27784 in f5 nginx_open_source?

Review vendor-specific security notices and update f5 nginx_open_source 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-2026-27784?

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-2026-27784?

CVE-2026-27784 is classified with a CVSS 3.1 Base Score of 7.8 (HIGH). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
7.8
HIGH SEVERITY
CVE ID CVE-2026-27784
Weakness CWE-190
Vendor f5
Product nginx_open_source
Published 2026-03-24
Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H