GHSA-cmm3-54f8-px4j: High severity maven/io.netty:netty-codec-classes-quic vulnerability

Published Jun 8, 2026
·
Updated

NoQuicTokenHandler is the tokenHandler used when the application does not set one. 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 quicheaccept 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.

Affected Software

1 affected componentFixes available
maven/io.netty:netty-codec-classes-quic>=4.2.0.Final<=4.2.14.Final
4.2.15.Final

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade maven/io.netty:netty-codec-classes-quic to a version that resolves this vulnerability.

    Fixed in 4.2.15.Final

Event History

Jun 8, 2026
Advisory Published
via GitHub·10:59 PM
Data Sourced
via GitHub·10:59 PM
DescriptionSeverityWeaknessAffected Software

Frequently Asked Questions

1

What is the severity of GHSA-cmm3-54f8-px4j?

The severity of GHSA-cmm3-54f8-px4j is classified as high with a score of 7.5.

2

How do I fix GHSA-cmm3-54f8-px4j?

To fix GHSA-cmm3-54f8-px4j, upgrade to the latest version of netty-codec-classes-quic.

3

What software is affected by GHSA-cmm3-54f8-px4j?

GHSA-cmm3-54f8-px4j affects maven/io.netty:netty-codec-classes-quic.

4

What is the impact of GHSA-cmm3-54f8-px4j?

The impact of GHSA-cmm3-54f8-px4j is a denial of service due to a vulnerability in token validation.

5

Is there a known exploit for GHSA-cmm3-54f8-px4j?

As of now, there are no public exploits reported for GHSA-cmm3-54f8-px4j.

Contact

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