HIGH CVSS 8.6
Published: 2026-07-10

CVE-2026-52747

owasp modsecurity Security Advisory (CVE-2026-52747)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-52747 impacting owasp modsecurity. Evaluated with CVSS Base Score of 8.6 (HIGH).

Original NVD Description

Source: NIST NVD
ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. Prior to 3.0.16, the multipart/form-data request body parser in libmodsecurity silently removes embedded line breaks from non-file form-field values before exporting them to ARGS and ARGS_POST because src/request_body_processor/multipart.cc overwrites reserved bytes in m_reserve instead of appending the current buffer. This creates a parser differential between ModSecurity and backend applications that preserve line breaks in form fields, allowing rules that inspect ARGS or ARGS_POST to miss payloads whose dangerous syntax depends on a line break. This issue is fixed in version 3.0.16.

📊 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
None (UI:N)
Zero human interaction required
Scope
Changed (S:C)
Impacts components beyond caller authority
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 owasp / modsecurity
Affected Versions *
Weakness Enumeration CWE-180

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-2026-52747 impacting owasp modsecurity.

⚡ Nuclei Detection Template (YAML) cve-2026-52747.yaml
id: cve-2026-52747

info:
  name: owasp modsecurity - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: high
  description: |
    Automated signature & scanner for CVE-2026-52747 affecting owasp modsecurity.
    Evaluation: ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. Prior to 3.0.16, the multipart/form-dat...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-52747
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N
    cvss-score: 8.6
    cve-id: CVE-2026-52747
    cwe-id: CWE-180
  tags: cve,cve-2026-52747,owasp,modsecurity,high

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "modsecurity"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-52747.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-52747
# Target: owasp modsecurity | CVSS: 8.6 (HIGH)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-52747 (owasp modsecurity)...")
    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 owasp modsecurity 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-2026-52747.sh
# Recommended Remediation & Patching Commands for CVE-2026-52747
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install modsecurity 2>/dev/null || \
sudo dnf upgrade modsecurity 2>/dev/null || \
sudo yum update modsecurity

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

# 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-2026-52747 in owasp modsecurity?

Review vendor-specific security notices and update owasp modsecurity 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-2026-52747?

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-2026-52747?

CVE-2026-52747 is classified with a CVSS 3.1 Base Score of 8.6 (HIGH). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
8.6
HIGH SEVERITY
CVE ID CVE-2026-52747
Weakness CWE-180
Vendor owasp
Product modsecurity
Published 2026-07-10
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N