Sign in Sign up
JA · EN · FR
SecPulse
Categories
CVE-2026-47691 high CVSS 8.7

Vulnerability in io.netty:netty-resolver-dns (CVE-2026-47691)

Summary

Vulnerability in io.netty:netty-resolver-dns (CVE-2026-47691). Confidential information can be exposed externally. Exploitable via DnsResolveContext. Mitigation: upgrade to 4.1.135.Final or later.

Original description

The description as published by the source.

Summary

Netty's DnsResolveContext insufficiently validates the bailiwick of NS records, enabling DNS Cache Poisoning. An attacker controlling an authoritative name server for a subdomain can poison the cache for parent domains (like .co.uk).

Details

In io.netty.resolver.dns.DnsResolveContext.AuthoritativeNameServerList#add method accepts any NS record from the AUTHORITY section as long as the record's name is a suffix of the questionName.

This means if the resolver queries evil.co.uk., it will accept an NS record claiming authority over co.uk.. Subsequently, the handleWithAdditional method caches the associated A records from the ADDITIONAL section directly into the authoritativeDnsServerCache under the parent domain's key (co.uk.). This bypasses standard bailiwick rules, where a server authoritative for a subdomain should not be trusted to provide authoritative records for its parent. The poisoned cache is then used for all future resolutions under co.uk..

The io.netty.resolver.dns.DnsResolveContext.AuthoritativeNameServerList#cache method only prevents caching if the record is for the root zone (dots == 1).

Impact

DNS Cache Poisoning. Any application using Netty's DNS resolver is impacted.

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-2026-47691 has been found in io.netty:netty-resolver-dns.
Attackers can target a specific entry point like DnsResolveContext over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 8.7/10.
What to do: upgrade io.netty:netty-resolver-dns to 4.1.135.Final or later.
If unsure, ask your IT team or search "io.netty:netty-resolver-dns CVE-2026-47691" on the vendor's site.

CVE-2026-47691 (io.netty:netty-resolver-dns) — CWE-345 / CVSS v3 8.7
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: DnsResolveContext / handleWithAdditional / authoritativeDnsServerCache
Patched: 4.1.135.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-345) exists in io.netty:netty-resolver-dns. Attackers reach the vulnerable code path via DnsResolveContext without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of io.netty:netty-resolver-dns. Attack surface: DnsResolveContext / handleWithAdditional / authoritativeDnsServerCache.

🔥 Severity

Severity: High (CVSS 8.7/10). Confidential information can be exposed externally.

🔧 How to fix

Update to 4.1.135.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-resolver-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-resolver-dns to 4.1.135.Final

    ステージング環境で 4.1.135.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-resolver-dns
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.1.135.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