Vulnerability in io.netty:netty-codec-classes-quic (CVE-2026-44894)
Summary
Vulnerability in io.netty:netty-codec-classes-quic (CVE-2026-44894). Data can be tampered with by attackers. Mitigation: upgrade to 4.2.15.Final or later.
Original description
The description as published by the source.
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.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-44894 has been found in io.netty:netty-codec-classes-quic.
Data can be tampered with by attackers. CVSS score: 7.5/10.
What to do: upgrade io.netty:netty-codec-classes-quic to 4.2.15.Final or later.
If unsure, ask your IT team or search "io.netty:netty-codec-classes-quic CVE-2026-44894" on the vendor's site.
CVE-2026-44894 (io.netty:netty-codec-classes-quic) — CWE-940 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: 4.2.15.Final — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-940) exists in io.netty:netty-codec-classes-quic.
Check the vendor advisory for the affected versions of io.netty:netty-codec-classes-quic.
Severity: High (CVSS 7.5/10). Data can be tampered with by attackers.
Update to 4.2.15.Final.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで io.netty:netty-codec-classes-quic を使っているサービスとバージョンを洗い出す。
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2Apply patch patch
Upgrade io.netty:netty-codec-classes-quic to 4.2.15.Finalステージング環境で 4.2.15.Final に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
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3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-44894 netty
- Ubuntu UBUNTU-CVE-2026-44894 netty
References
- advisory github.com
- advisory nvd.nist.gov
- advisory access.redhat.com
- advisory github.com
- package github.com
- report bugzilla.redhat.com
- web github.com
- web github.com
- web security.access.redhat.com