MEDIUM CVSS 5.4
Published: 2026-06-18

CVE-2026-43915

coturn_project coturn Security Advisory (CVE-2026-43915)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-43915 impacting coturn_project coturn. Evaluated with CVSS Base Score of 5.4 (MEDIUM).

Original NVD Description

Source: NIST NVD
Coturn is a free open source implementation of TURN and STUN Server. Versions prior to 4.11.0 contain a stored cross-site scripting (XSS) vulnerability in the web-admin HTTPS interface. An attacker who can create a TURN allocation with a crafted USERNAME value can inject HTML/JavaScript that executes when an authenticated web-admin user views the TURN session list. In configurations using anonymous TURN access (--no-auth), this may be exploitable without TURN credentials. In authenticated deployments, exploitation requires valid TURN credentials or control over a provisioned username. This issue has been fixed in version 4.11.0.

📊 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
Low (PR:L)
Standard user access required
User Interaction
Required (UI:R)
User must click or open resource
Scope
Changed (S:C)
Impacts components beyond caller authority
Confidentiality
Low (C:L)
Partial information leakage
Integrity
Low (I:L)
Partial data modification possible
Availability
None (A:N)
No system availability impact

🎯 Affected Versions Matrix

Affected Product coturn_project / coturn
Affected Versions *
Weakness Enumeration CWE-79

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-2026-43915 impacting coturn_project coturn.

⚡ Nuclei Detection Template (YAML) cve-2026-43915.yaml
id: cve-2026-43915

info:
  name: coturn_project coturn - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: medium
  description: |
    Automated signature & scanner for CVE-2026-43915 affecting coturn_project coturn.
    Evaluation: Coturn is a free open source implementation of TURN and STUN Server. Versions prior to 4.11.0 contain a stored cross-site scripting (XSS) vulnerabilit...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-43915
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
    cvss-score: 5.4
    cve-id: CVE-2026-43915
    cwe-id: CWE-79
  tags: cve,cve-2026-43915,coturn_project,coturn,medium

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "coturn"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-43915.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-43915
# Target: coturn_project coturn | CVSS: 5.4 (MEDIUM)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-43915 (coturn_project coturn)...")
    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 coturn_project coturn 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-2026-43915.sh
# Recommended Remediation & Patching Commands for CVE-2026-43915
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install coturn 2>/dev/null || \
sudo dnf upgrade coturn 2>/dev/null || \
sudo yum update coturn

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

# 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-2026-43915 in coturn_project coturn?

Review vendor-specific security notices and update coturn_project coturn 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-2026-43915?

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-2026-43915?

CVE-2026-43915 is classified with a CVSS 3.1 Base Score of 5.4 (MEDIUM). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
5.4
MEDIUM SEVERITY
CVE ID CVE-2026-43915
Weakness CWE-79
Vendor coturn_project
Product coturn
Published 2026-06-18
Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N