MEDIUM CVSS 6.6
Published: 2026-06-25

CVE-2026-57438

nokogiri nokogiri Security Advisory (CVE-2026-57438)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-57438 impacting nokogiri nokogiri. Evaluated with CVSS Base Score of 6.6 (MEDIUM).

Original NVD Description

Source: NIST NVD
Nokogiri is an open source XML and HTML library for the Ruby programming language. Prior to 1.19.4, XInclude substitution performed by Nokogiri::XML::Node#do_xinclude replaced each <xi:include> in place, freeing the include node along with its children (such as <xi:fallback> and its descendants) and any namespaces declared on them. If an application had already exposed one of those nodes or namespaces to Ruby, the corresponding Ruby object was left pointing at freed memory. Using the object could result in invalid reads or writes to memory. This vulnerability is fixed in 1.19.4.

📊 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
Low (C:L)
Partial information leakage
Integrity
Low (I:L)
Partial data modification possible
Availability
High (A:H)
Total denial of service or shutdown

🎯 Affected Versions Matrix

Affected Product nokogiri / nokogiri
Affected Versions *
Weakness Enumeration CWE-416

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-2026-57438 impacting nokogiri nokogiri.

⚡ Nuclei Detection Template (YAML) cve-2026-57438.yaml
id: cve-2026-57438

info:
  name: nokogiri nokogiri - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: medium
  description: |
    Automated signature & scanner for CVE-2026-57438 affecting nokogiri nokogiri.
    Evaluation: Nokogiri is an open source XML and HTML library for the Ruby programming language. Prior to 1.19.4, XInclude substitution performed by Nokogiri::XML::...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-57438
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H
    cvss-score: 6.6
    cve-id: CVE-2026-57438
    cwe-id: CWE-416
  tags: cve,cve-2026-57438,nokogiri,nokogiri,medium

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "nokogiri"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-57438.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-57438
# Target: nokogiri nokogiri | CVSS: 6.6 (MEDIUM)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-57438 (nokogiri nokogiri)...")
    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 nokogiri nokogiri 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-2026-57438.sh
# Recommended Remediation & Patching Commands for CVE-2026-57438
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install nokogiri 2>/dev/null || \
sudo dnf upgrade nokogiri 2>/dev/null || \
sudo yum update nokogiri

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

# 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-2026-57438 in nokogiri nokogiri?

Review vendor-specific security notices and update nokogiri nokogiri 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-2026-57438?

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-2026-57438?

CVE-2026-57438 is classified with a CVSS 3.1 Base Score of 6.6 (MEDIUM). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
6.6
MEDIUM SEVERITY
CVE ID CVE-2026-57438
Weakness CWE-416
Vendor nokogiri
Product nokogiri
Published 2026-06-25
Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H