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NettyApplication

CVE-2026-44890

HIGH · 7.5 CVSS v3.1 Published 2026-06-11
Fix available
A fix is available. Upgrade to 4.1.135 / 4.2.15 or later.
See remediation →
84/100
Remediation priority · High
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. In netty-codec-redis prior to versions 4.1.135.Final and 4.2.15.Final, an attacker can cause DoS by sending crafted Redis payloads across multiple connections without `\r\n`. This exhausts the server's direct memory pool (OutOfDirectMemoryError), preventing legitimate connections from being processed. 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

In netty-codec-redis, the Redis protocol parser fails to properly handle malformed messages without proper line endings (\r\n). When an attacker sends crafted Redis payloads across multiple connections missing these delimiters, the parser accumulates direct memory buffers without releasing them, causing OutOfDirectMemoryError and DoS.

MitigationUpgrade netty-codec-redis to version 4.1.135.Final or 4.2.15.Final which contain the fix for proper buffer cleanup on malformed Redis messages.

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
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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

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 Netty version in use
    Run 'mvn dependency:tree | grep netty' for Maven projects, or check your build.gradle/pom.xml for netty version, or inspect the netty-common-[version].jar file in your classpath
    Affected if The Netty version is less than 4.1.135 or greater than or equal to 4.2.0 but less than 4.2.15
  2. Confirm netty-codec-redis module is present
    Check your project dependencies for netty-codec-redis (Maven: 'netty-codec-redis', Gradle: 'io.netty:netty-codec-redis')
    Affected if netty-codec-redis is listed as a direct or transitive dependency in your project
  3. Verify Redis codec decoder is configured
    Search your codebase for 'RedisDecoder' or 'Codecs.newRedisDecoder()' - these indicate the vulnerable decoder is being initialized in your Netty pipeline
    Affected if RedisDecoder is instantiated and added to a ChannelPipeline in your application
  4. Confirm direct memory is in use
    Check JVM startup arguments for '-XX:MaxDirectMemorySize' or inspect Netty's 'io.netty.maxDirectMemory' metric if exposed via JMX/monitoring
    Affected if Direct memory is allocated (default or custom) and the application accepts Redis connections from untrusted sources

You are affected if your application uses a vulnerable Netty version (below 4.1.135 or 4.2.0-4.2.14) AND includes the netty-codec-redis module with RedisDecoder enabled in the pipeline, accepting Redis protocol connections from network sources.

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-codec-redis to version 4.1.135.Final or 4.2.15.Final which contain the fix for proper buffer cleanup on malformed Redis messages.

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 current Netty version in use (check pom.xml, build.gradle, or dependency management)
  2. If using Netty 4.1.x branch: upgrade netty-all or netty-bom to version 4.1.135.Final
  3. If using Netty 4.2.x branch: upgrade netty-all or netty-bom to version 4.2.15.Final
  4. For Maven: Update <version> in pom.xml dependency, then run 'mvn clean compile' to verify
  5. For Gradle: Update version in build.gradle dependencies, then run './gradlew build' to verify
  6. Run application tests to confirm functionality is intact
  7. Deploy updated application to production
Caveat None mentioned in the advisory; this appears to be a bug-fix release addressing the resource exhaustion vulnerability

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

Fix this in Netty Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,190
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,904.

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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-2026-44890 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