CyberSecBulletin
CVE-2026-42587NVD status: Modified

netty: Uncontrolled Resource Consumption

Published Updated By the CyberSecBulletin desk

CVE-2026-42587 is a high-severity uncontrolled resource consumption vulnerability in netty, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected netty versions: >= 4.2.0.Alpha1, < 4.2.13.Final; < 4.1.133.Final. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.99% chance of exploitation within 30 days, higher than 63% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Check which version of netty you run against the affected versions below, and install the vendor's latest release.
  2. Read the advisory on github.com for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
Nettynetty>= 4.2.0.Alpha1, < 4.2.13.Final; < 4.1.133.FinalNot stated
Io.nettynetty-codec-http>= 4.2.0.Alpha1, < 4.2.13.Final; < 4.1.133.FinalNot stated
Io.nettynetty-codec-http2>= 4.2.0.Alpha1, < 4.2.13.Final; < 4.1.133.FinalNot stated
Red HatCryostat 4 on RHEL 9Not specified in the recordNot stated
Red HatRed Hat AMQ Broker 7.13.6Not specified in the recordNot stated
Red HatRed Hat AMQ Broker 7.14.1Not specified in the recordNot stated
Red HatRed Hat build of Apache Camel 4.18.1.P1 for Spring Boot 3.5.16Not specified in the recordNot stated
Red HatRed Hat build of Quarkus 3.27.4Not specified in the recordNot stated
Red HatRed Hat build of Quarkus 3.33.2Not specified in the recordNot stated
Red HatRed Hat Data Grid 8.6.2Not specified in the recordNot stated
Red HatRed Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 7Not specified in the recordNot stated
Red HatRed Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 8Not specified in the recordNot stated
Red HatRed Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 9Not specified in the recordNot stated
Red HatRed Hat JBoss Enterprise Application Platform 8.1Not specified in the recordNot stated
Red HatRed Hat JBoss Enterprise Application Platform 8.1.7.GANot specified in the recordNot stated
Red HatRed Hat JBoss Enterprise Application Platform 8.1 for RHEL 10Not specified in the recordNot stated
Red HatRed Hat JBoss Enterprise Application Platform 8.1 for RHEL 8Not specified in the recordNot stated
Red HatRed Hat JBoss Enterprise Application Platform 8.1 for RHEL 9Not specified in the recordNot stated
Red HatStreams for Apache Kafka 2.9.4Not specified in the recordNot stated
Red HatStreams for Apache Kafka 3.2.1Not specified in the recordNot stated
Red HatRed Hat OpenShift AI 2.25Not specified in the recordNot stated
Red HatRed Hat OpenShift Dev Spaces 3.28Not specified in the recordNot stated
Red HatRed Hat OpenShift Dev Spaces 3.29Not specified in the recordNot stated
Red HatCryostat 4Not specified in the recordNot stated
Red HatOpenShift ServerlessNot specified in the recordNot stated

Version data comes from the organisation that assigned the CVE; 15 further products are omitted here. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
NoneNo data is disclosed.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CNA (github.com).

Scoring systemScoreSeverityScored by
CVSS 3.17.5HighCNA (github.com)
CVSS 3.17.5HighCNA

Official description

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, HttpContentDecompressor accepts a maxAllocation parameter to limit decompression buffer size and prevent decompression bomb attacks. This limit is correctly enforced for gzip and deflate encodings via ZlibDecoder, but is silently ignored when the content encoding is br (Brotli), zstd, or snappy. An attacker can bypass the configured decompression limit by sending a compressed payload with Content-Encoding: br instead of Content-Encoding: gzip, causing unbounded memory allocation and out-of-memory denial of service. The same vulnerability exists in DelegatingDecompressorFrameListener for HTTP/2 connections. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Uncontrolled Resource Consumption

The product does not properly control the allocation and maintenance of a limited resource.

How developers prevent this class of flaw

  • Ensure that protocols have specific limits of scale placed on them.
  • Ensure that all failures in resource allocation place the system into a safe posture.

More Uncontrolled Resource Consumption vulnerabilities (CWE-400)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in netty

All netty vulnerabilities

Recent Uncontrolled Resource Consumption vulnerabilities

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