CVE-2026-48043: netty-codec-http2 ByteBuf Reference-Count Leak Vulnerability

MODERATE
Advisory Identifier: GHSA-c2gf-v879-257j
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CVSS 5.3
CWE-400 CWE-772 CWE-401
Published
Advisory Summary

CVE-2026-48043 is a MODERATE (CVSS 5.3) bytebuf reference-count leak vulnerability (CWE-400: Uncontrolled Resource Consumption) affecting netty-codec-http2 libraries in the Maven ecosystem. The issue involves bytebuf reference-count leak in delegatingdecompressorframelistener leads to memory exhaustion. Remediation is available by upgrading affected packages to version 4.2.15.Final, 4.1.135.Final.

CVE-2026-48043 at a Glance

CVE Identifier CVE-2026-48043
GHSA Identifier GHSA-c2gf-v879-257j
Severity MODERATE
CVSS v3.1 Base Score 5.3
CWE Classification CWE-400: Uncontrolled Resource Consumption
Affected Product netty-codec-http2
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 5.3

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability Low (A:L)

How to Fix CVE-2026-48043

To remediate this vulnerability, upgrade all affected netty-codec-http2 dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

io.netty:netty-codec-http2 fixed: 4.2.15.Final 
<dependency>
    <groupId>io.netty</groupId>
    <artifactId>netty-codec-http2</artifactId>
    <version>4.2.15.Final</version>
</dependency>
io.netty:netty-codec-http2 fixed: 4.1.135.Final 
<dependency>
    <groupId>io.netty</groupId>
    <artifactId>netty-codec-http2</artifactId>
    <version>4.1.135.Final</version>
</dependency>
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree -Dincludes=io.netty

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-48043, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=io.netty

Analyze the terminal output to locate any version of netty-codec-http2 in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 4.2.15.Final), your application is affected.

Note: The mvn dependency:tree -Dincludes=io.netty command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-400: Uncontrolled Resource Consumption, where the product does not properly control the allocation and maintenance of a limited resource. In netty-codec-http2, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Impact The `DelegatingDecompressorFrameListener` class orchestrates HTTP/2 decompression by embedding a per-stream `EmbeddedChannel` that runs the appropriate decompression codec (gzip, deflate, zstd) and forwards decompressed chunks to a wrapped listener. Each decompressed chunk is a pooled `ByteBuf` handed to an anonymous `ChannelInboundHandlerAdapter` tail handler, which becomes the sole owner responsible for releasing it. A remote peer could send frames that would result in the flow-controller throwing and so trigger a resource leak which at the end might take down the whole JVM due OOME.

CVE-2026-48043 Affected netty-codec-http2 Versions

2 component(s)
Fixed Versions:
4.2.15.Final4.1.135.Final
Product / Package Ecosystem Affected Versions Fixed Version
io.netty:netty-codec-http2
maven/io.netty/netty-codec-http2
Maven
≥ 4.2.0.Alpha1
< 4.2.15.Final
4.2.15.Final
io.netty:netty-codec-http2
maven/io.netty/netty-codec-http2
Maven
< 4.1.135.Final
4.1.135.Final

References

GitHub Advisory / Wiki ADVISORY
https://github.com/netty/netty/security/advisories/GHSA-c2gf-v879-257j
NVD — CVE-2026-48043 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-48043
Security Fix Commit FIX COMMIT
https://github.com/netty/netty/commit/db6138b168699736a6463c367e12ad0a4c36a25e
Security Fix Commit FIX COMMIT
https://github.com/netty/netty/commit/3d45a1e4e8eb99144f716e54be5ac57e525fa7ca
netty-codec-http2 Security Information SECURITY
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-48043.json
netty-codec-http2 Release RELEASE
https://github.com/netty/netty/releases/tag/netty-4.2.15.Final
netty-codec-http2 Release RELEASE
https://github.com/netty/netty/releases/tag/netty-4.1.135.Final
netty-codec-http2 Source Repository REPOSITORY
https://github.com/netty/netty
bugzilla.redhat.com/show_bug.cgi WEB
https://bugzilla.redhat.com/show_bug.cgi?id=2488442
netty-codec-http2 Security Information SECURITY
https://access.redhat.com/security/cve/CVE-2026-48043
access.redhat.com/errata/rhsa-2026:66... WEB
https://access.redhat.com/errata/RHSA-2026:66488
access.redhat.com/errata/rhsa-2026:65... WEB
https://access.redhat.com/errata/RHSA-2026:65126
access.redhat.com/errata/rhsa-2026:54... WEB
https://access.redhat.com/errata/RHSA-2026:54435
access.redhat.com/errata/rhsa-2026:53... WEB
https://access.redhat.com/errata/RHSA-2026:53806
access.redhat.com/errata/rhsa-2026:53... WEB
https://access.redhat.com/errata/RHSA-2026:53646
access.redhat.com/errata/rhsa-2026:53... WEB
https://access.redhat.com/errata/RHSA-2026:53645
access.redhat.com/errata/rhsa-2026:53... WEB
https://access.redhat.com/errata/RHSA-2026:53644
access.redhat.com/errata/rhsa-2026:50... WEB
https://access.redhat.com/errata/RHSA-2026:50085
access.redhat.com/errata/rhsa-2026:48... WEB
https://access.redhat.com/errata/RHSA-2026:48151
access.redhat.com/errata/rhsa-2026:48... WEB
https://access.redhat.com/errata/RHSA-2026:48124
access.redhat.com/errata/rhsa-2026:41... WEB
https://access.redhat.com/errata/RHSA-2026:41951
access.redhat.com/errata/rhsa-2026:37... WEB
https://access.redhat.com/errata/RHSA-2026:37390
access.redhat.com/errata/rhsa-2026:36... WEB
https://access.redhat.com/errata/RHSA-2026:36820
access.redhat.com/errata/rhsa-2026:34... WEB
https://access.redhat.com/errata/RHSA-2026:34608
access.redhat.com/errata/rhsa-2026:26... WEB
https://access.redhat.com/errata/RHSA-2026:26586
access.redhat.com/errata/rhsa-2026:26... WEB
https://access.redhat.com/errata/RHSA-2026:26018
access.redhat.com/errata/rhsa-2026:26... WEB
https://access.redhat.com/errata/RHSA-2026:26017

Frequently Asked Questions

What is CVE-2026-48043?
CVE-2026-48043 is a security vulnerability in netty-codec-http2 involving ByteBuf Reference-Count Leak in DelegatingDecompressorFrameListener Leads to Memory Exhaustion under CWE-400: Uncontrolled Resource Consumption.
Which netty-codec-http2 versions are affected?
Affected versions include releases prior to 4.2.15.Final, 4.1.135.Final across affected packages: io.netty:netty-codec-http2.
What version fixes CVE-2026-48043?
Upgrading to 4.2.15.Final, 4.1.135.Final (or the latest patched release for your respective branch) resolves the vulnerability.
Is netty-codec-http2 affected?
Yes, io.netty:netty-codec-http2 is affected in releases prior to 4.2.15.Final, 4.1.135.Final. Upgrade your dependency to 4.2.15.Final, 4.1.135.Final or later.
What is the CVSS score of CVE-2026-48043?
CVE-2026-48043 has a CVSS v3.1 base score of 5.3 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.
What CWE is associated with CVE-2026-48043?
CVE-2026-48043 is classified under CWE-400: Uncontrolled Resource Consumption (The product does not properly control the allocation and maintenance of a limited resource.).
How can I check Maven dependencies for CVE-2026-48043?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=io.netty'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
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