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Fencer Vulns
high 7.5

CVE-2026-33871 json

Netty HTTP/2 CONTINUATION Frame Flood DoS via Zero-Byte Frame Bypass

published 2026-03-26 7 mo ago modified 2026-09-15 54 d ago also GHSA-w9fj-cfpg-grvv , EUVD-2026-16790

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.3%
EPSS 1.3% chance of exploitation in 30 days, percentile 71%
public exploits
0
none known

Summary

Netty is an asynchronous, event-driven network application framework. In versions prior to 4.1.132.Final and 4.2.10.Final, a remote user can trigger a Denial of Service (DoS) against a Netty HTTP/2 server by sending a flood of `CONTINUATION` frames. The server's lack of a limit on the number of `CONTINUATION` frames, combined with a bypass of existing size-based mitigations using zero-byte frames, allows an user to cause excessive CPU consumption with minimal bandwidth, rendering the server unresponsive. Versions 4.1.132.Final and 4.2.10.Final fix the issue.

Patch / fix

  • maven io.netty:netty-codec-http2 4.1.132.Final, 4.2.11.Final
  • Red Hat Cryostat 4 on RHEL 9 4.2.0-9
  • Red Hat Red Hat AMQ Broker 7.12.7 codec-http2
  • Red Hat Red Hat AMQ Broker 7.13.5 codec-http2
  • Red Hat Red Hat AMQ Broker 7.14.0 codec-http2
  • Red Hat Red Hat Build of Apache Camel 4.14 for Quarkus 3.27 codec-http2
  • Red Hat Red Hat build of Apache Camel 4.18.1 for Spring Boot 3.5.14 codec-http2
  • Red Hat Red Hat build of Quarkus 3.20.6 codec-http2
  • Red Hat Red Hat build of Quarkus 3.27.3 codec-http2
  • Red Hat Red Hat Data Grid 8.6.1 codec-http2
  • Red Hat Red Hat JBoss Enterprise Application Platform 8.1 http-4.1.100.Final.jar
  • Red Hat Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 8 0:4.1.132-1.Final_redhat_00001.1.el8eap
  • Red Hat Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 9 0:4.1.132-1.Final_redhat_00001.1.el9eap
  • Red Hat Streams for Apache Kafka 2.9.4 codec-http2
  • Red Hat Red Hat OpenShift AI 2.25 1776756834, 1788198681
  • Red Hat Red Hat OpenShift Dev Spaces 3.27 1776716842, 1776717247, 1776796445
  • eap8-angus jboss enterprise application platform 8.1 2.0.5-1.redhat_00001.1.el8eap
  • eap8-guava jboss enterprise application platform 8.1 33.0.0-3.jre_redhat_00004.1.el8eap
  • eap8-netty jboss enterprise application platform 8.1 4.1.132-1.Final_redhat_00001.1.el8eap
  • eap8-yasson jboss enterprise application platform 8.1 3.0.4-5.redhat_00007.1.el8eap
  • eap8-jctools jboss enterprise application platform 8.1 4.0.6-1.redhat_00001.1.el8eap
  • eap8-wildfly jboss enterprise application platform 8.1 8.1.6-5.GA_redhat_00007.1.el8eap
  • eap8-hibernate jboss enterprise application platform 8.1 6.6.48-1.Final_redhat_00001.1.el8eap
  • eap8-angus-mail jboss enterprise application platform 8.1 2.0.5-1.redhat_00001.1.el8eap

red hat advisories RHSA-2026:18054RHSA-2026:18055

  • netty-tcnative SLE Module for Development Tools 15 SP7, openSUSE Leap 15.6 2.0.75-150200.3.36.1
  • netty SLE Module for Package Hub 15 SP7, openSUSE Leap 15.6 4.1.132-150200.4.43.1

suse advisories SUSE-SU-2026:1353-1

  • netty openSUSE Tumbleweed 4.1.132-1.1

opensuse advisories openSUSE-SU-2026:10463-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-33871 updated cvss 7.5

netty: Netty: Denial of Service via HTTP/2 CONTINUATION frame flood

  • Red Hat Cryostat 4 netty-codec-http2 Red Hat Logging Subsystem for Red Hat OpenShift openshift-logging/kibana6-rhel8, openshift-logging/elasticsearch6-rhel9, openshift-logging/logging-curator5-rhel9, openshift-logging/elasticsearch-proxy-rhel9, openshift-logging/elasticsearch-rhel9-operator, openshift-logging/elasticsearch-operator-bundle
    affected: no fix available
  • Red Hat OpenShift Serverless openshift-serverless-1/kn-ekb-receiver-rhel9, openshift-serverless-1/kn-ekb-dispatcher-rhel9, openshift-serverless-1/kn-eventing-integrations-log-sink-rhel9, openshift-serverless-1/kn-eventing-integrations-aws-s3-sink-rhel9, openshift-serverless-1/kn-eventing-integrations-aws-sns-sink-rhel9, openshift-serverless-1/kn-eventing-integrations-aws-sqs-sink-rhel9, +4 more
    affected: no fix available, no fix planned “Will not fix”
  • Red Hat AMQ Clients netty-codec-http Red Hat build of Apache Camel - HawtIO 4 netty-codec-http, netty-codec-http2 Red Hat build of Apache Camel 4 for Quarkus 3 netty-codec-http, netty-codec-http2
    affected: no fix available
  • Red Hat build of Apicurio Registry 2 netty-codec-http, netty-codec-http2
    affected: no fix planned “Will not fix”
  • Red Hat build of Apicurio Registry 3 netty-codec-http, netty-codec-http2
    affected: no fix available
  • Red Hat build of Debezium 2 netty-codec-http, netty-codec-http2
    affected: no fix available “Fix deferred”
  • Red Hat build of Debezium 3 netty-codec-http, netty-codec-http2
    affected: no fix planned “Will not fix”
  • Red Hat Build of Keycloak netty-codec-http, netty-codec-http2
    affected: no fix available
show 25 more
  • Red Hat build of OptaPlanner 8 netty-codec-http, netty-codec-http2
    affected: no fix planned “Will not fix”
  • Red Hat build of Quarkus netty-codec-http2 Red Hat Enterprise Linux AI (RHEL AI) 3 bazel6, bazel7, bazel8
    affected: no fix available
  • Red Hat Fuse 7 netty-codec-http, netty-codec-http2 Red Hat JBoss Enterprise Application Platform 7 netty-codec-http, netty-codec-http2
    affected: no fix planned “Will not fix”
  • Red Hat JBoss Enterprise Application Platform 8 netty-codec-http-4.1.100.Final.jar
    affected: no fix available
  • Red Hat JBoss Enterprise Application Platform Expansion Pack netty-codec-http2, netty-codec-http2-4.1.100.Final.jar, netty-codec-http2-4.1.128.Final-redhat-00001.jar
    affected: no fix available, no fix planned “Will not fix”
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-modelmesh-rhel8
    affected: no fix available
  • Red Hat Process Automation 7 netty-codec-http, netty-codec-http2 Red Hat Single Sign-On 7 netty-codec-http, netty-codec-http2
    affected: no fix planned “Will not fix”
  • Red Hat Cryostat 4 on RHEL 9 cryostat/cryostat-rhel9 4.2.0-9, cryostat/jfr-datasource-rhel9 4.2.0-9, cryostat/cryostat-reports-rhel9 4.2.0-9
    fixed: vendor fix RHSA-2026:17789
  • Red Hat AMQ Broker 7.12.7
    fixed: vendor fix RHSA-2026:14276
  • Red Hat AMQ Broker 7.13.5
    fixed: vendor fix RHSA-2026:14272
  • Red Hat AMQ Broker 7.14.0
    fixed: vendor fix RHSA-2026:8509
  • Red Hat Build of Apache Camel 3.27.1.SP1 netty-codec-http2 4.1.128.Final-redhat-00001
    fixed: vendor fix RHSA-2026:8159
  • Red Hat build of Apache Camel 4.18.1 for Spring Boot 3.5.14
    fixed: vendor fix RHSA-2026:17668
  • Red Hat build of Quarkus 3.20.6.redhat netty-codec-http2 4.1.132.Final-redhat-00001
    fixed: vendor fix RHSA-2026:7109
  • Red Hat build of Quarkus 3.27.3.redhat netty-codec-http2 4.1.132.Final-redhat-00001
    fixed: vendor fix RHSA-2026:7380
  • Red Hat Data Grid 8.6.1
    fixed: vendor fix RHSA-2026:22619
  • Red Hat JBoss EAP 8.1 for RHEL 8 eap8-netty 4.1.132-1.Final_redhat_00001.1.el8eap, eap8-netty-codec 4.1.132-1.Final_redhat_00001.1.el8eap, eap8-netty-buffer 4.1.132-1.Final_redhat_00001.1.el8eap, eap8-netty-common 4.1.132-1.Final_redhat_00001.1.el8eap, eap8-netty-handler 4.1.132-1.Final_redhat_00001.1.el8eap, eap8-netty-resolver 4.1.132-1.Final_redhat_00001.1.el8eap, +9 more
    fixed: vendor fix RHSA-2026:18054
  • Red Hat JBoss EAP 8.1 for RHEL 9 eap8-netty 4.1.132-1.Final_redhat_00001.1.el9eap, eap8-netty-codec 4.1.132-1.Final_redhat_00001.1.el9eap, eap8-netty-buffer 4.1.132-1.Final_redhat_00001.1.el9eap, eap8-netty-common 4.1.132-1.Final_redhat_00001.1.el9eap, eap8-netty-handler 4.1.132-1.Final_redhat_00001.1.el9eap, eap8-netty-resolver 4.1.132-1.Final_redhat_00001.1.el9eap, +9 more
    fixed: vendor fix RHSA-2026:18055
  • Red Hat JBoss Enterprise Application Platform 6.0.4.GA netty-codec-http2 4.1.132.Final-redhat-00001
    fixed: vendor fix RHSA-2026:19678
  • Red Hat JBoss Enterprise Application Platform 8.1.6.GA netty-codec-http 4.1.132.Final-redhat-00001
    fixed: vendor fix RHSA-2026:18059
  • Red Hat OpenShift AI 2.25 rhoai 1776756834, rhoai/odh-trustyai-service-rhel9 1788198681
    fixed: vendor fix RHSA-2026:10184
  • Red Hat OpenShift Dev Spaces 3.27 devspaces 1776716842, devspaces 1776717247, devspaces 1776796445
    fixed: vendor fix RHSA-2026:10175
  • Red Hat Streams for Apache Kafka 2.9.4
    fixed: vendor fix RHSA-2026:34608
  • Red Hat Streams for Apache Kafka 3.2.0
    fixed: vendor fix RHSA-2026:13571
  • Red Hat Cryostat 4 on RHEL 9 cryostat/cryostat-db-rhel9 4.2.0-13, cryostat/cryostat-storage-rhel9 4.2.0-13, cryostat/cryostat-operator-bundle 4.2.0-7, cryostat/cryostat-rhel9-operator 4.2.0-13, cryostat/cryostat-agent-init-rhel9 0.7.0-7, cryostat/cryostat-grafana-dashboard-rhel9 4.2.0-9, +1 more Red Hat Build of Apache Camel 3.27.1.SP1 jimfs 1.1, jna 5.8.0, s3 2.32.4, bcel 6.7.0, bson 5.5.1, gax 2.57.0, +1536 more
    not affected: vulnerable code not present

13 more not affected in the full advisory

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
7 mo ago

Exploit prediction

1.33% chance of exploitation in the next 30 days, higher than 71% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
maven io.netty:netty-codec-http2
<4.1.132.Final
>=4.2.0.Alpha1, <4.2.11.Final
4.1.132.Final
4.2.11.Final

Affected products

  • netty netty
  • Red Hat Cryostat 4 on RHEL 9
  • Red Hat Red Hat AMQ Broker 7.12.7
  • Red Hat Red Hat AMQ Broker 7.13.5
  • Red Hat Red Hat AMQ Broker 7.14.0
  • Red Hat Red Hat Build of Apache Camel 4.14 for Quarkus 3.27
  • Red Hat Red Hat build of Apache Camel 4.18.1 for Spring Boot 3.5.14
  • Red Hat Red Hat build of Quarkus 3.20.6
  • Red Hat Red Hat build of Quarkus 3.27.3
  • Red Hat Red Hat Data Grid 8.6.1
  • Red Hat Red Hat JBoss Enterprise Application Platform 8.1
  • Red Hat Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 8
  • Red Hat Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 9
  • Red Hat Streams for Apache Kafka 2.9.4
  • Red Hat Streams for Apache Kafka 3.2.0
  • Red Hat Red Hat OpenShift AI 2.25
  • Red Hat Red Hat OpenShift Dev Spaces 3.27
  • Red Hat Cryostat 4
  • Red Hat Logging Subsystem for Red Hat OpenShift
  • Red Hat OpenShift Serverless
  • Red Hat Red Hat AMQ Clients
  • Red Hat Red Hat build of Apache Camel 4 for Quarkus 3
  • Red Hat Red Hat build of Apache Camel - HawtIO 4
  • Red Hat Red Hat build of Apicurio Registry 2
  • Red Hat Red Hat build of Apicurio Registry 3
  • Red Hat Red Hat build of Debezium 2
  • Red Hat Red Hat build of Debezium 3
  • Red Hat Red Hat Build of Keycloak
  • Red Hat Red Hat build of OptaPlanner 8
  • Red Hat Red Hat build of Quarkus
  • Red Hat Red Hat Enterprise Linux AI (RHEL AI) 3
  • Red Hat Red Hat Fuse 7
  • Red Hat Red Hat JBoss Enterprise Application Platform 7
  • Red Hat Red Hat JBoss Enterprise Application Platform 8
  • Red Hat Red Hat JBoss Enterprise Application Platform Expansion Pack
  • Red Hat Red Hat OpenShift AI (RHOAI)
  • Red Hat Red Hat Process Automation 7
  • Red Hat Red Hat Satellite 6
  • Red Hat Red Hat Single Sign-On 7
  • Red Hat streams for Apache Kafka 3

Classification

Weakness
  • CWE-770 Allocation of Resources Without Limits or Throttling
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.