Sign in Sign up
JA · EN · FR
SecPulse
Categories
CVE-2026-42579 high CVSS 7.5

Vulnerability in io.netty:netty-codec-dns (CVE-2026-42579)

Summary

Vulnerability in io.netty:netty-codec-dns (CVE-2026-42579). Data can be tampered with by attackers. Exploitable via io.netty.handler.codec.dns.DnsCodecUtil. Mitigation: upgrade to 4.1.133.Final or later.

Original description

The description as published by the source.

Security Vulnerability Report: DNS Codec Input Validation Bypass in Netty (Encoder + Decoder)

1. Vulnerability Summary

Field Value
Product Netty
Version 4.2.12.Final (and all prior versions with codec-dns)
Component io.netty.handler.codec.dns.DnsCodecUtil
Vulnerability Type CWE-20: Improper Input Validation / CWE-626: Null Byte Interaction Error / CWE-400: Uncontrolled Resource Consumption
Impact DNS Cache Poisoning / Domain Validation Bypass / Denial of Service / Malformed DNS Packets

2. Affected Components

Both the encoder and decoder in the same file are affected:

  • io.netty.handler.codec.dns.DnsCodecUtil — encodeDomainName() method (lines 31-51):

    • No null byte validation in domain name labels
    • No per-label length validation (RFC 1035 max: 63 bytes)
    • No total domain name length validation (RFC 1035 max: 255 bytes)
    • Empty labels silently truncate the domain name

  • io.netty.handler.codec.dns.DnsCodecUtil — decodeDomainName() method (lines 53-118):

    • No per-label length validation (max 63)
    • No total domain name length validation (max 255)
    • Unbounded StringBuilder growth from attacker-controlled DNS responses

3. Vulnerability Description

Netty's DNS codec does not enforce RFC 1035 domain name constraints during either encoding or decoding. This creates a bidirectional attack surface: malicious DNS responses can exploit the decoder, and user-influenced…

Source: NIST National Vulnerability Database 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-2026-42579 has been found in io.netty:netty-codec-dns.
Attackers can target a specific entry point like io.netty.handler.codec.dns.DnsCodecUtil over the network to misuse the product.
Data can be tampered with by attackers. CVSS score: 7.5/10.
What to do: upgrade io.netty:netty-codec-dns to 4.1.133.Final or later.
If unsure, ask your IT team or search "io.netty:netty-codec-dns CVE-2026-42579" on the vendor's site.

CVE-2026-42579 (io.netty:netty-codec-dns) — CWE-20 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: io.netty.handler.codec.dns.DnsCodecUtil / DnsNameResolver
Patched: 4.1.133.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.

❓ What is the problem

A vulnerability (CWE-20) exists in io.netty:netty-codec-dns. Attackers reach the vulnerable code path via io.netty.handler.codec.dns.DnsCodecUtil without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of io.netty:netty-codec-dns. Attack surface: io.netty.handler.codec.dns.DnsCodecUtil / DnsNameResolver.

🔥 Severity

Severity: High (CVSS 7.5/10). Data can be tampered with by attackers.

🔧 How to fix

Update to 4.1.133.Final.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

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

  1. 1
    Identify 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-dns を使っているサービスとバージョンを洗い出す。

  2. 2
    Apply patch patch 
    Upgrade io.netty:netty-codec-dns to 4.1.133.Final

    ステージング環境で 4.1.133.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。

  3. 3
    Post-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

maven io.netty:netty-codec-dns
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.1.133.Final"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

We use cookies for analytics and ad measurement. This setting applies to all Game co., Ltd. sites. Details