CVE-2026-48748
Undergoing Analysis Undergoing Analysis - In Progress
Memory Exhaustion in Netty HTTP/3 Codec

Publication date: 2026-06-12

Last updated on: 2026-06-12

Assigner: GitHub, Inc.

Description
Netty is a network application framework for development of protocol servers and clients. 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.
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Meta Information
Published
2026-06-12
Last Modified
2026-06-12
Generated
2026-06-12
AI Q&A
2026-06-12
EPSS Evaluated
N/A
NVD
CVE-2026-48748
EUVD
EUVD-2026-36459
Affected Vendors & Products
Showing 2 associated CPEs
Vendor Product Version / Range
netty netty to 4.2.15.Final (exc)
netty netty_codec_http3 From 4.2.0.Final (inc) to 4.2.14.Final (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-770 The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.
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Compliance Impact

The provided information does not specify any direct impact of this vulnerability on compliance with common standards and regulations such as GDPR or HIPAA.

Executive Summary

CVE-2026-48748 is a memory exhaustion vulnerability in Netty's HTTP/3 codec. It allows attackers to create an infinite number of blocked streams when QPACK dynamic tables are enabled and the maxBlockedStreams setting is left at its default value of 0. This causes the QpackDecoder to fail to remove unblocked streams from memory, leading to excessive memory consumption and eventually an Out-of-Memory (OOM) error that crashes the Java Virtual Machine (JVM).

Impact Analysis

This vulnerability can lead to a Denial of Service (DoS) attack by causing the affected server to run out of memory and crash. Since exploitation requires no privileges or user interaction, an attacker can easily trigger the issue remotely, disrupting the availability of services relying on Netty's HTTP/3 codec versions 4.2.0.Final to 4.2.13.Final with QPACK dynamic tables enabled and default maxBlockedStreams configuration.

Detection Guidance

This vulnerability can be detected by checking if your system is running a vulnerable version of Netty's HTTP/3 codec (versions 4.2.0.Final to 4.2.13.Final) with QPACK dynamic tables enabled and no explicit maxBlockedStreams configuration.

You can verify the Netty version used by your application by inspecting your dependency management files or runtime environment.

Additionally, monitoring your system for symptoms such as excessive memory usage or JVM crashes related to Out-of-Memory (OOM) errors may indicate exploitation attempts.

  • Check the Netty HTTP/3 codec version in your application dependencies (e.g., using Maven: mvn dependency:list | grep netty-codec-http3).
  • Inspect runtime JVM parameters or logs for OOM errors or crashes.
  • Review your Netty HTTP/3 codec configuration to see if QPACK dynamic tables are enabled and if maxBlockedStreams is set explicitly.
Mitigation Strategies

To mitigate this vulnerability immediately, upgrade your Netty HTTP/3 codec to version 4.2.15.Final or later, where the issue is patched.

If upgrading is not immediately possible, configure the maxBlockedStreams setting explicitly to a non-zero value to limit the number of blocked streams and prevent memory exhaustion.

Monitor your system for unusual memory usage and JVM stability to detect potential exploitation attempts.

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