Cyber Resilience

CVE-2026-44894

Netty 4.2.0 – 4.2.15

Published
12 June 2026
Modified
15 July 2026
Patch / advisory
View advisory
CVSS Score v3.1 7.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
EPSS Score 0.0014 4th percentile
Risk Priority 56 floored blend · peak EPSS

Summary

CVE-2026-44894 is a high-severity Improper Verification of Source of a Communication Channel (CWE-940) vulnerability in Netty Netty. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique ARP Cache Poisoning (T1557.002); ranked at the 4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to AC-17 (Remote Access) and AC-4 (Information Flow Enforcement) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A07:2025 Authentication Failures

EU & UK References

Vulnerability Data

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 — acceptable),…

more

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 §8.1, a validated address lifts the 3× anti-amplification send limit. Thus any attacker who includes ANY non-empty token bytes in an Initial packet — with a spoofed victim source IP — causes the Netty server to treat the victim as validated and reflect full-size handshake flights (certificates, etc.) toward it without the 3× 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.

CWE(s)
CWE-940CWE-346

Related Threats

MITRE ATT&CK Enterprise Techniques

T1557.002 ARP Cache Poisoning Credential Access
Adversaries may poison Address Resolution Protocol (ARP) caches to position themselves between the communication of two or more networked devices.
attack.mitre.org →
T1557.003 DHCP Spoofing Credential Access
Adversaries may redirect network traffic to adversary-owned systems by spoofing Dynamic Host Configuration Protocol (DHCP) traffic and acting as a malicious DHCP server on the victim network.
attack.mitre.org →
T1557 Adversary-in-the-Middle Credential Access
Adversaries may attempt to position themselves between two or more networked devices using an adversary-in-the-middle (AiTM) technique to support follow-on behaviors such as [Network Sniffing](https://attack.
attack.mitre.org →
T1557.001 Name Resolution Poisoning and SMB Relay Credential Access
By responding to LLMNR/NBT-NS/mDNS network traffic, adversaries may spoof an authoritative source for name resolution to force communication with an adversary controlled system.
attack.mitre.org →
T1557.004 Evil Twin Credential Access
Adversaries may host seemingly genuine Wi-Fi access points to deceive users into connecting to malicious networks as a way of supporting follow-on behaviors such as [Network Sniffing](https://attack.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-45674Same product: Netty Netty
CVE-2026-47691Same product: Netty Netty
CVE-2026-56820Same product: Netty Netty
CVE-2025-58056Same product: Netty Netty
CVE-2026-33870Same product: Netty Netty
CVE-2026-42584Same product: Netty Netty
CVE-2026-42581Same product: Netty Netty
CVE-2026-42585Same product: Netty Netty
CVE-2026-50020Same product: Netty Netty
CVE-2026-42578Same product: Netty Netty

Affected Assets

netty
netty
4.2.0 — 4.2.15

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 3 hardening rules · 1 OS baseline
Validate
Prove the fix (OWASP ASVS)
  • V3.5.3
  • V10.6.2
  • V15.2.4

Mitigating Controls (NIST 800-53 r5) AI

IA-3 Device Identification and Authentication good match

IA-3 requires unique identification and authentication of devices before any communication channel is established, directly stopping acceptance of unverified origins.

AC-17 Remote Access good match

AC-17 mandates documented restrictions and authentication requirements for remote access, blocking channels whose origins are not properly verified.

AC-4 Information Flow Enforcement good match

Information flow enforcement directly requires validating the source of data before allowing transmission or receipt.

SC-23 Session Authenticity good match

Session authenticity mechanisms require validation that communications originate from the expected party.

SC-7 Boundary Protection partial match

SC-7 enforces monitoring and control at external and key internal interfaces, preventing channels from unverified sources via boundary rules.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-03 full match
prevents

Authentication of users/services/hardware directly enforces source verification for communication channels.

PR.AA-04 mostly match
prevents

Verifying identity assertions prevents spoofed channel origins but does not cover all channel-establishment scenarios.

ID.AM-03 partial match
prevents

Documenting authorized flows supports origin validation by defining expected sources.

PR.IR-01 partial match
prevents

Network protections reduce unauthorized channel usage but do not specifically require origin verification at channel setup.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.5 Secure authentication mostly match
prevents

Secure authentication mechanisms verify the identity and origin of communication channel initiators.

A.8.20 Networks security partial match
degrades

Network security controls enforce source verification and channel authentication for incoming communications.

A.8.21 Security of network services partial match
degrades

Security of network services includes validating the origin of service requests and connections.

A.8.22 Segregation of networks partial match
mitigates

Network segregation limits exposure but does not directly verify source of individual channels.

A.8.24 Use of cryptography partial match
prevents

Cryptography can support channel authentication but does not inherently verify source without proper implementation.

A.8.26 Application security requirements partial match
prevents

Application security requirements may specify origin checks but do not mandate them.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (3 rules)
  • V-248574 YUM must be configured to prevent the installation of patches, service packs, device drivers, or OL 8 system components that have not been digitally signed using a certificate that is recognized and approved by the organization. prevents CWE-346
  • V-248575 OL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-346
  • V-248827 OL 8 must not have the rsh-server package installed. prevents CWE-346

References