MEDIUM CVSS 6.4
Published: 2021-02-25

CVE-2021-20328

mongodb java_driver Security Advisory (CVE-2021-20328)
โ†— Official NIST NVD Record
Seeking technical exploit breakdowns or verified PoC code for CVE-2021-20328?
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2021-20328 impacting mongodb java_driver. Evaluated with CVSS Base Score of 6.4 (MEDIUM).

Original NVD Description

Source: NIST NVD
Specific versions of the Java driver that support client-side field level encryption (CSFLE) fail to perform correct host name verification on the KMS serverโ€™s certificate. This vulnerability in combination with a privileged network position active MITM attack could result in interception of traffic between the Java driver and the KMS service rendering Field Level Encryption ineffective. This issue was discovered during internal testing and affects all versions of the Java driver that support CSFLE. The Java async, Scala, and reactive streams drivers are not impacted. This vulnerability does not impact driver traffic payloads with CSFLE-supported key services originating from applications residing inside the AWS, GCP, and Azure network fabrics due to compensating controls in these environments. This issue does not impact driver workloads that donโ€™t use Field Level Encryption.

๐Ÿ“Š CVSS v3.1 Metric Breakdown

Attack Vector
Adjacent (AV:A)
Requires shared subnet / local network access
Attack Complexity
High (AC:H)
Depends on race conditions or environment
Privileges Required
None (PR:N)
Unauthenticated execution
User Interaction
Required (UI:R)
User must click or open resource
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
None (A:N)
No system availability impact

๐ŸŽฏ Affected Versions Matrix

Affected Product mongodb / java_driver
Affected Versions *
Weakness Enumeration CWE-295

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-2021-20328 impacting mongodb java_driver.

โšก Nuclei Detection Template (YAML) cve-2021-20328.yaml
id: cve-2021-20328

info:
  name: mongodb java_driver - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: medium
  description: |
    Automated signature & scanner for CVE-2021-20328 affecting mongodb java_driver.
    Evaluation: Specific versions of the Java driver that support client-side field level encryption (CSFLE) fail to perform correct host name verification on the KMS...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2021-20328
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
    cvss-score: 6.4
    cve-id: CVE-2021-20328
    cwe-id: CWE-295
  tags: cve,cve-2021-20328,mongodb,java_driver,medium

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "java_driver"
        part: body
๐Ÿ PoC Exploit & Verification Probe (Python 3) poc_cve-2021-20328.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2021-20328
# Target: mongodb java_driver | CVSS: 6.4 (MEDIUM)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2021-20328 (mongodb java_driver)...")
    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 mongodb java_driver 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)
๐Ÿ›ก๏ธ Quick Patch & Remediation Script (Bash) patch_cve-2021-20328.sh
# Recommended Remediation & Patching Commands for CVE-2021-20328
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install java_driver 2>/dev/null || \
sudo dnf upgrade java_driver 2>/dev/null || \
sudo yum update java_driver

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

# 3. Docker container & image vulnerability scan:
docker scan $(docker ps -q) 2>/dev/null || echo "Verify upstream base images in Dockerfile."

๐Ÿ›ก๏ธ 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.
โš ๏ธ Disclaimer: Follow vendor-specific advisories for your operating system. CyberVault does not fabricate unsupported remediation scripts.

๐Ÿ”— Verified Technical References

Authorities
  • No records filed in this category.
Distributions
  • No records filed in this category.

โ“ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2021-20328 in mongodb java_driver?

Review vendor-specific security notices and update mongodb java_driver 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-2021-20328?

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-2021-20328?

CVE-2021-20328 is classified with a CVSS 3.1 Base Score of 6.4 (MEDIUM). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
6.4
MEDIUM SEVERITY
CVE ID CVE-2021-20328
Weakness CWE-295
Vendor mongodb
Product java_driver
Published 2021-02-25
Vector CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N