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NettyApplication

CVE-2026-45674

CRITICAL · 10.0 CVSS v3.1 Published 2026-06-12
Fix available
A fix is available. Upgrade to 4.1.135 / 4.2.15 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, Netty's DnsResolveContext fails to validate the origin (bailiwick) of CNAME records in DNS responses. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Netty's DnsResolveContext does not validate the origin (bailiwick) of CNAME records in DNS responses before versions 4.1.135.Final and 4.2.15.Final. This allows attackers to inject malicious CNAME records pointing to arbitrary domains, potentially enabling DNS rebinding or cache poisoning attacks.

MitigationUpgrade Netty to version 4.1.135.Final or 4.2.15.Final or later. If immediate upgrade is not possible, implement additional DNS response validation at the application layer.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
NettyApplication
Affected:< 4.1.135>= 4.2.0, < 4.2.15

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed Netty version
    Check your project's dependency management file (Maven pom.xml, Gradle build.gradle) or inspect the netty-common JAR manifest for the version attribute. Run: grep -r 'netty' pom.xml or list the netty-*.jar files in your classpath.
    Affected if The Netty version is below 4.1.135 or between 4.2.0 and 4.2.14 (inclusive)
  2. Confirm netty-resolver dependency is in use
    Verify that the netty-resolver or netty-resolver-dns module is included in your application dependencies. This module contains DnsResolveContext. Check your build dependencies or runtime classpath.
    Affected if The netty-resolver-dns module is present in your runtime dependencies
  3. Determine if DNS resolution is performed
    Inspect code for usage of DnsNameResolver, DnsResolveContext, or related DNS resolution classes. Search for imports of io.netty.resolver.dns.* or calls to resolve methods on DnsNameResolver.
    Affected if Your application uses DnsNameResolver or DnsResolveContext to resolve DNS records
  4. Check if CNAME processing occurs
    Review whether your DNS resolver configuration processes CNAME records. This is the default behavior in DnsResolveContext when handling DNS responses. Examine any custom DnsRecordResolver or DnsNameResolverBuilder configurations.
    Affected if The default DNS resolution path is used, which automatically processes CNAME records from responses

You are affected if your application uses Netty's DNS resolver (netty-resolver-dns) with a version in the vulnerable range (below 4.1.135 or between 4.2.0 and 4.2.14) and processes CNAME records from DNS responses, as the missing bailiwick validation allows malicious CNAME injection.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 4.1.135 / 4.2.15 or later
Fixed in 4.1.1354.2.15
Interim mitigation

Upgrade Netty to version 4.1.135.Final or 4.2.15.Final or later. If immediate upgrade is not possible, implement additional DNS response validation at the application layer.

Recommended fix High confidence

4.1.135.Final (for 4.1.x users) or 4.2.15.Final (for 4.2.x users)

  1. Identify the current Netty version in use by checking project dependencies (Maven pom.xml, Gradle build.gradle, or similar)
  2. For Maven projects, update the netty version in pom.xml to 4.1.135.Final (for 4.1.x line) or 4.2.15.Final (for 4.2.x line)
  3. For Gradle projects, update the netty dependency version to '4.1.135.Final' or '4.2.15.Final'
  4. Run dependency resolution to verify the correct version is pulled (e.g., mvn dependency:tree or gradle dependencies)
  5. Rebuild the project and run tests to ensure the upgrade does not break existing functionality

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Netty Scoped from the published advisory
  • Consultation3.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,920
Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-45674 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data