MEDIUM CVSS 4.4
Published: 2020-12-04

CVE-2020-16123

canonical ubuntu_linux Security Advisory (CVE-2020-16123)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2020-16123 impacting canonical ubuntu_linux. Evaluated with CVSS Base Score of 4.4 (MEDIUM).

Original NVD Description

Source: NIST NVD
An Ubuntu-specific patch in PulseAudio created a race condition where the snap policy module would fail to identify a client connection from a snap as coming from a snap if SCM_CREDENTIALS were missing, allowing the snap to connect to PulseAudio without proper confinement. This could be exploited by an attacker to expose sensitive information. Fixed in 1:13.99.3-1ubuntu2, 1:13.99.2-1ubuntu2.1, 1:13.99.1-1ubuntu3.8, 1:11.1-1ubuntu7.11, and 1:8.0-0ubuntu3.15.

📊 CVSS v3.1 Metric Breakdown

Attack Vector
Local (AV:L)
Requires local system execution permissions
Attack Complexity
High (AC:H)
Depends on race conditions or environment
Privileges Required
Low (PR:L)
Standard user access required
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
None (I:N)
No system modification impact
Availability
None (A:N)
No system availability impact

🎯 Affected Versions Matrix

Affected Product canonical / ubuntu_linux
Affected Versions 16.04
Weakness Enumeration CWE-362

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-2020-16123 impacting canonical ubuntu_linux.

⚡ Nuclei Detection Template (YAML) cve-2020-16123.yaml
id: cve-2020-16123

info:
  name: canonical ubuntu_linux - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: medium
  description: |
    Automated signature & scanner for CVE-2020-16123 affecting canonical ubuntu_linux.
    Evaluation: An Ubuntu-specific patch in PulseAudio created a race condition where the snap policy module would fail to identify a client connection from a snap as...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2020-16123
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:N/A:N
    cvss-score: 4.4
    cve-id: CVE-2020-16123
    cwe-id: CWE-362
  tags: cve,cve-2020-16123,canonical,ubuntu_linux,medium

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "ubuntu_linux"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2020-16123.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2020-16123
# Target: canonical ubuntu_linux | CVSS: 4.4 (MEDIUM)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2020-16123 (canonical ubuntu_linux)...")
    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 canonical ubuntu_linux scope (16.04).")
        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-2020-16123.sh
# Recommended Remediation & Patching Commands for CVE-2020-16123
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install ubuntu_linux 2>/dev/null || \
sudo dnf upgrade ubuntu_linux 2>/dev/null || \
sudo yum update ubuntu_linux

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

# 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

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2020-16123 in canonical ubuntu_linux?

Review vendor-specific security notices and update canonical ubuntu_linux 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-2020-16123?

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-2020-16123?

CVE-2020-16123 is classified with a CVSS 3.1 Base Score of 4.4 (MEDIUM). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
4.4
MEDIUM SEVERITY
CVE ID CVE-2020-16123
Weakness CWE-362
Vendor canonical
Product ubuntu_linux
Published 2020-12-04
Vector CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:N/A:N