Netty's Default QUIC token handler accepts any client-supplied token
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 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.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Java / Kotlin (Maven) | io.netty:netty-codec-classes-quic | >= 4.2.0.Final, < 4.2.15.Final | 4.2.15.Final |
References
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N- Weakness (CWE)
CWE-940- Platform
- Java / Kotlin (Maven)
- Package
io.netty:netty-codec-classes-quic- Disclosed
- 08.06.2026
- Updated
- 11.10.2026 13:20
Sources and licenses
OSV / GitHub Advisory Database - GHSA-cmm3-54f8-px4j - CC BY 4.0
Vulnerability history: io.netty:netty-codec-classes-quic
All published vulnerabilities of this package (Java / Kotlin (Maven)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 2
- First → latest
- 06.2026 06.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 1
- Medium 1
Disclosures per year
- 2026: 2
-
Netty's Default QUIC token handler accepts any client-supplied token this entry
Know which vulnerabilities affect your application
With the DockRay integration and software inventory enabled, DockRay checks reported component versions against known vulnerabilities and notifies you about confirmed matches. Coverage depends on the supported technology and available advisory data.