CyberSecBulletin
CVE-2026-42584NVD status: Modified

netty: Inconsistent Interpretation of HTTP Requests

Published Updated By the CyberSecBulletin desk

CVE-2026-42584 is a critical-severity inconsistent interpretation of HTTP requests vulnerability in netty, with a CVSS 3.1 base score of 9.1 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 0.84% chance of exploitation within 30 days, higher than 58% of scored CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

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
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 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 8.1.7.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 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 HatOpenShift ServerlessNot specified in the recordNot stated
Red HatRed Hat AMQ ClientsNot specified in the recordNot stated
Red HatRed Hat build of Apache Camel 4 for Quarkus 3Not specified in the recordNot stated
Red HatRed Hat build of Apicurio Registry 2Not specified in the recordNot stated
Red HatRed Hat build of Apicurio Registry 3Not specified in the recordNot stated
Red HatRed Hat build of Debezium 3Not specified in the recordNot stated

Version data comes from the organisation that assigned the CVE; 11 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
HighData or code can be modified at will.
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:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.17.3HighCNA (github.com)
CVSS 3.19.1CriticalNVD
CVSS 3.17.3HighCNA

Official description

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, HttpClientCodec pairs each inbound response with an outbound request by queue.poll() once per response, including for 1xx. If the client pipelines GET then HEAD and the server sends 103, then 200 with GET body, then 200 for HEAD, the queue pairs HEAD with the first 200. The HEAD rule then skips reading that message’s body, so the GET entity bytes stay on the stream and the following 200 is parsed from the wrong offset. 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: Inconsistent Interpretation of HTTP Requests

The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.

How developers prevent this class of flaw

  • Use a web server that employs a strict HTTP parsing procedure, such as Apache.
  • Terminate the client session after each request.

More Inconsistent Interpretation of HTTP Requests vulnerabilities (CWE-444)

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 Inconsistent Interpretation of HTTP Requests vulnerabilities

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