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NettyApplication

CVE-2026-48748

HIGH · 7.5 CVSS v3.1 Published 2026-06-12
Fix available
A fix is available. Upgrade to 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. Starting in version 4.2.0.Final and prior to version 4.2.15.Final, a memory exhaustion vulnerability in the Netty HTTP/3 codec allows the creation of an infinite number of blocked streams, which can cause OOM error. Version 4.2.15.Final patches 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 HTTP/3 codec prior to version 4.2.15.Final contains a memory exhaustion vulnerability where an attacker can create an infinite number of blocked streams, leading to Out-Of-Memory (OOM) errors and denial of service.

MitigationUpgrade Netty to version 4.2.15.Final or later to patch the memory exhaustion vulnerability in the HTTP/3 codec.

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:>= 4.2.0, < 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 dependency in use
    Check your project's dependency manifest (Maven pom.xml, Gradle build.gradle, or similar) for 'io.netty:netty' or 'io.netty:netty-all' dependencies and note the version number
    Affected if The Netty version is 4.2.0 through 4.2.14 inclusive
  2. Verify HTTP/3 codec is enabled
    Search your codebase for HTTP/3 server or client configuration that uses the Netty HTTP/3 codec classes (look for Http3 or HTTP/3 related setup code, or check if netty-http3 or http2 dependencies are included)
    Affected if HTTP/3 codec is configured and in use with a vulnerable Netty version
  3. Confirm stream configuration
    Check the HTTP/3 server or pipeline configuration for stream-related settings - look for maxConcurrentStreams, initialWindowSize, or similar HTTP/3 stream window parameters that control how many streams can be created
    Affected if Stream limits are not properly configured or are set to allow excessive concurrent streams (specific values depend on your configuration, but an attacker exploiting this would trigger unlimited blocked stream creation)
  4. Check for memory pressure indicators
    Monitor JVM memory usage (heap and direct memory) during HTTP/3 traffic - look for growing memory consumption that correlates with incoming requests, particularly streams that become blocked
    Affected if Memory grows unbounded during HTTP/3 request handling and does not get released, indicating potential exploitation of this vulnerability

You are affected if Netty version 4.2.0-4.2.14 is in use AND the HTTP/3 codec is enabled, as this combination allows attackers to trigger unlimited blocked stream creation leading to OOM.

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 4.2.15 or later
Fixed in 4.2.15
Interim mitigation

Upgrade Netty to version 4.2.15.Final or later to patch the memory exhaustion vulnerability in the HTTP/3 codec.

Recommended fix High confidence

4.2.15.Final

  1. 1. Identify all dependencies on Netty in your project using build tools (Maven, Gradle, etc.)
  2. 2. Locate the Netty HTTP/3 codec dependency (typically io.netty:netty-codec-http3 or similar)
  3. 3. Update the Netty version to 4.2.15.Final or later in your dependency management
  4. 4. Rebuild and test your application to ensure compatibility
  5. 5. Deploy the updated application

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

Fix this in Netty Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing6.0 h
  • Review / QA3.0 h
15.0 hours of engineering $2,600
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,160.

Scan for this in your stack

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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-2026-48748 in production — separate from our analysis above.

No notes yet

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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