HIGH CVSS 7.5
Published: 2026-06-12

CVE-2026-44894

netty netty Security Advisory (CVE-2026-44894)
โ†— Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-44894 impacting netty netty. Evaluated with CVSS Base Score of 7.5 (HIGH).

Original NVD Description

Source: NIST NVD
Netty is a network application framework for development of protocol servers and clients. NoQuicTokenHandler is the tokenHandler used when the application does not set one. Prior to version 4.2.15.Final, its writeToken() returns false (server will not send Retry โ€” acceptable), but validateToken() unconditionally `return 0`. In QuicheQuicServerCodec.handlePacket(), a non-negative return from validateToken() is interpreted as 'token is valid, ODCID starts at offset 0', causing the server to call quiche_accept as if the client's address had been validated by a Retry round-trip. Per RFC 9000 ยง8.1, a validated address lifts the 3ร— anti-amplification send limit. Thus any attacker who includes ANY non-empty token bytes in an Initial packet โ€” with a spoofed victim source IP โ€” causes the Netty server to treat the victim as validated and reflect full-size handshake flights (certificates, etc.) toward it without the 3ร— cap. The correct 'no token handler' semantics would be to return -1 (invalid) so the normal un-validated path and amplification limit apply. Version 4.2.15.Final patches the issue.

๐Ÿ“Š 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
None (C:N)
No data confidentiality impact
Integrity
High (I:H)
Total modification of target system
Availability
None (A:N)
No system availability impact

๐ŸŽฏ Affected Versions Matrix

Affected Product netty / netty
Affected Versions *
Weakness Enumeration CWE-940

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-2026-44894 impacting netty netty.

โšก Nuclei Detection Template (YAML) cve-2026-44894.yaml
id: cve-2026-44894

info:
  name: netty netty - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: high
  description: |
    Automated signature & scanner for CVE-2026-44894 affecting netty netty.
    Evaluation: Netty is a network application framework for development of protocol servers and clients. NoQuicTokenHandler is the tokenHandler used when the applica...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-44894
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
    cvss-score: 7.5
    cve-id: CVE-2026-44894
    cwe-id: CWE-940
  tags: cve,cve-2026-44894,netty,netty,high

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "netty"
        part: body
๐Ÿ PoC Exploit & Verification Probe (Python 3) poc_cve-2026-44894.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-44894
# Target: netty netty | 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-2026-44894 (netty netty)...")
    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 netty netty 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-2026-44894.sh
# Recommended Remediation & Patching Commands for CVE-2026-44894
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install netty 2>/dev/null || \
sudo dnf upgrade netty 2>/dev/null || \
sudo yum update netty

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

# 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.

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

How do I fix CVE-2026-44894 in netty netty?

Review vendor-specific security notices and update netty netty 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-2026-44894?

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-2026-44894?

CVE-2026-44894 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-2026-44894
Weakness CWE-940
Vendor netty
Product netty
Published 2026-06-12
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N