CVE-2026-44894 | Netty's Default QUIC token handler accepts any client-supplied token

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.

Published: 2026-06-12 Last update: 2026-06-12 Assigner: [email protected] Source: [email protected]
NVD Status：Undergoing Analysis，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-44894 is rated Low Risk (31.2/100): CVSS High severity, with low exploitation likelihood (EPSS 0.01%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-44894

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-12 — 0.01% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-44894

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 3.6 [email protected]

Weakness enumeration for CVE-2026-44894

GitHub Security Advisory for CVE-2026-44894

GHSA-cmm3-54f8-px4j · Severity: high · Ecosystem: maven — Netty's Default QUIC token handler accepts any client-supplied token

OS Trackers for CVE-2026-44894

vendor priority summary link
debian not yet assigned CVE-2026-44894 not yet assigned priority: Debian including 1 source packages (netty), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 5. https://security-tracker.debian.org/tracker/CVE-2026-44894
redhat high — https://access.redhat.com/security/cve/CVE-2026-44894

Affected software / configurations for CVE-2026-44894

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2026-44894

cvelogic Threat Intelligence