MEDIUM CVSS 6.8
Published: 2014-01-21

CVE-2013-0340

libexpat_project libexpat Security Advisory (CVE-2013-0340)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2013-0340 impacting libexpat_project libexpat. Evaluated with CVSS Base Score of 6.8 (MEDIUM).

Original NVD Description

Source: NIST NVD
expat before version 2.4.0 does not properly handle entities expansion unless an application developer uses the XML_SetEntityDeclHandler function, which allows remote attackers to cause a denial of service (resource consumption), send HTTP requests to intranet servers, or read arbitrary files via a crafted XML document, aka an XML External Entity (XXE) issue. NOTE: it could be argued that because expat already provides the ability to disable external entity expansion, the responsibility for resolving this issue lies with application developers; according to this argument, this entry should be REJECTed, and each affected application would need its own CVE.

📊 CVSS v3.1 Metric Breakdown

Attack Vector
Network (AV:N)
Exploitable remotely across internet boundaries

🎯 Affected Versions Matrix

Affected Product libexpat_project / libexpat
Affected Versions *
Weakness Enumeration CWE-611

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-2013-0340 impacting libexpat_project libexpat.

⚡ Nuclei Detection Template (YAML) cve-2013-0340.yaml
id: cve-2013-0340

info:
  name: libexpat_project libexpat - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: medium
  description: |
    Automated signature & scanner for CVE-2013-0340 affecting libexpat_project libexpat.
    Evaluation: expat before version 2.4.0 does not properly handle entities expansion unless an application developer uses the XML_SetEntityDeclHandler function, whi...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2013-0340
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:M/Au:N/C:P/I:P/A:P
    cvss-score: 6.8
    cve-id: CVE-2013-0340
    cwe-id: CWE-611
  tags: cve,cve-2013-0340,libexpat_project,libexpat,medium

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "libexpat"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2013-0340.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2013-0340
# Target: libexpat_project libexpat | CVSS: 6.8 (MEDIUM)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2013-0340 (libexpat_project libexpat)...")
    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 libexpat_project libexpat 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-2013-0340.sh
# Recommended Remediation & Patching Commands for CVE-2013-0340
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install libexpat 2>/dev/null || \
sudo dnf upgrade libexpat 2>/dev/null || \
sudo yum update libexpat

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

# 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-2013-0340 in libexpat_project libexpat?

Review vendor-specific security notices and update libexpat_project libexpat 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-2013-0340?

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-2013-0340?

CVE-2013-0340 is classified with a CVSS 3.1 Base Score of 6.8 (MEDIUM). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
6.8
MEDIUM SEVERITY
CVE ID CVE-2013-0340
Weakness CWE-611
Vendor libexpat_project
Product libexpat
Published 2014-01-21
Vector AV:N/AC:M/Au:N/C:P/I:P/A:P