HIGH CVSS 7.5
Published: 2026-04-16

CVE-2026-40245

free5gc free5gc Security Advisory (CVE-2026-40245)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-40245 impacting free5gc free5gc. Evaluated with CVSS Base Score of 7.5 (HIGH).

Original NVD Description

Source: NIST NVD
Free5GC is an open-source Linux Foundation project for 5th generation (5G) mobile core networks. Versions 4.2.1 and below contain an information disclosure vulnerability in the UDR (Unified Data Repository) service. The handler for GET /nudr-dr/v2/application-data/influenceData/subs-to-notify sends an HTTP 400 error response when required query parameters are missing but does not return afterward. Execution continues into the processor function, which queries the data repository and appends the full list of Traffic Influence Subscriptions, including SUPI/IMSI values, to the response body. An unauthenticated attacker with network access to the 5G Service Based Interface can retrieve stored subscriber identifiers with a single parameterless HTTP GET request. The SUPI is the most sensitive subscriber identifier in 5G networks, and its exposure undermines the privacy guarantees of the 3GPP SUCI concealment mechanism at the core network level. A similar bypass exists when sending a malformed snssai parameter due to the same missing return pattern.

📊 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
None (PR:N)
Unauthenticated execution
User Interaction
None (UI:N)
Zero human interaction required
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 free5gc / free5gc
Affected Versions *
Weakness Enumeration CWE-200

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-2026-40245 impacting free5gc free5gc.

⚡ Nuclei Detection Template (YAML) cve-2026-40245.yaml
id: cve-2026-40245

info:
  name: free5gc free5gc - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: high
  description: |
    Automated signature & scanner for CVE-2026-40245 affecting free5gc free5gc.
    Evaluation: Free5GC is an open-source Linux Foundation project for 5th generation (5G) mobile core networks. Versions 4.2.1 and below contain an information discl...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-40245
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
    cvss-score: 7.5
    cve-id: CVE-2026-40245
    cwe-id: CWE-200
  tags: cve,cve-2026-40245,free5gc,free5gc,high

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "free5gc"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-40245.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-40245
# Target: free5gc free5gc | CVSS: 7.5 (HIGH)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-40245 (free5gc free5gc)...")
    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 free5gc free5gc 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-2026-40245.sh
# Recommended Remediation & Patching Commands for CVE-2026-40245
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install free5gc 2>/dev/null || \
sudo dnf upgrade free5gc 2>/dev/null || \
sudo yum update free5gc

# 2. Inspect installed package versions for vulnerable scope:
dpkg -l | grep -i free5gc 2>/dev/null || rpm -qa | grep -i free5gc

# 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-2026-40245 in free5gc free5gc?

Review vendor-specific security notices and update free5gc free5gc 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-2026-40245?

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-2026-40245?

CVE-2026-40245 is classified with a CVSS 3.1 Base Score of 7.5 (HIGH). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
7.5
HIGH SEVERITY
CVE ID CVE-2026-40245
Weakness CWE-200
Vendor free5gc
Product free5gc
Published 2026-04-16
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N