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), 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.
History

Fri, 12 Jun 2026 15:45:00 +0000

Type Values Removed Values Added
First Time appeared Netty
Netty netty
Vendors & Products Netty
Netty netty

Fri, 12 Jun 2026 14:30:00 +0000

Type Values Removed Values Added
Description 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), 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.
Title Netty's Default QUIC token handler accepts any client-supplied token
Weaknesses CWE-940
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-06-12T14:06:54.213Z

Reserved: 2026-05-07T21:50:33.545Z

Link: CVE-2026-44894

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Undergoing Analysis

Published: 2026-06-12T15:16:26.240

Modified: 2026-06-12T15:55:06.377

Link: CVE-2026-44894

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-06-12T15:30:31Z