Description
Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, SslClientHelloHandler.decode() reads the 24-bit TLS handshake length and, when the ClientHello does not fit in the first record, eagerly allocates `ctx.alloc().buffer(handshakeLength)` (line 161). The guard at line 140 is `handshakeLength > maxClientHelloLength && maxClientHelloLength != 0`, and the commonly-used SniHandler/AbstractSniHandler constructors (SniHandler(Mapping), SniHandler(AsyncMapping), AbstractSniHandler()) pass maxClientHelloLength=0 and handshakeTimeoutMillis=0, so the length guard is disabled and no timeout is scheduled. A 16 MiB request exceeds the default pooled chunk size and becomes a huge/unpooled allocation performed immediately. The buffer is retained in the handler until the channel closes. Versions 4.1.135.Final and 4.2.15.Final patch the issue.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| netty | netty | >= 4.2.0.Final, < 4.2.15.Final, < 4.1.135.Final | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | netty | No fix yet | — |
| Debian 13 | netty | No fix yet | — |
| Debian 12 | netty | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | netty | No fix yet | — |
| Ubuntu 25.10 | netty | No fix yet | — |
Show 7 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 26.04 LTS | netty | No fix yet | — |
| Ubuntu Pro 24.04 LTS | netty | No fix yet | — |
| Ubuntu Pro 22.04 LTS | netty | No fix yet | — |
| Ubuntu Pro 20.04 LTS | netty | No fix yet | — |
| Ubuntu Pro 18.04 LTS | netty | No fix yet | — |
| Ubuntu Pro 16.04 LTS | netty | No fix yet | — |
| Ubuntu Pro 14.04 LTS | netty | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Single Sign On 7 | rh-sso7-keycloak +1 | 18.0.20-1.redhat_00001.1.el7sso | RHSA-2026:76130, RHSA-2026:76129, RHSA-2026:76128 |
| Red Hat Jboss Enterprise Application Platform Els 7 | eap7-activemq-artemis +15 | 2.16.0-22.redhat_00057.1.el7eap | RHSA-2026:53644 |
| Red Hat Jboss Enterprise Application Platform Els 7 | eap7-glassfish-jsf | 2.3.14-11.SP11_redhat_00001.1.el7eap | RHSA-2026:53644 |
| Red Hat Jboss Enterprise Application Platform Els 7 | eap7-ironjacamar +8 | 1.5.26-2.Final_redhat_00001.1.el7eap | RHSA-2026:53644 |
| Red Hat Jboss Enterprise Application Platform Els 7 | eap7-jackson-core +10 | 2.18.8-1.redhat_00003.1.el7eap | RHSA-2026:53644 |
| Red Hat Jboss Enterprise Application Platform Els 7 | eap7-jboss-remoting | 5.0.31-3.SP2_redhat_00001.1.el7eap | RHSA-2026:53644 |
| Red Hat Jboss Enterprise Application Platform Els 7 | eap7-jboss-server-migration +2 | 1.10.0-46.Final_redhat_00044.1.el7eap | RHSA-2026:53644 |
| Red Hat Jboss Enterprise Application Platform Els 7 | eap7-netty +26 | 4.1.135-1.Final_redhat_00001.1.el7eap | RHSA-2026:53644 |
| Red Hat Jboss Enterprise Application Platform Els 7 | eap7-picketlink-api +7 | 2.5.5-24.SP12_redhat_00016.1.el7eap | RHSA-2026:53644 |
| Red Hat Jboss Enterprise Application Platform Els 7 | eap7-picketlink-bindings +1 | 2.5.5-30.SP12_redhat_00020.1.el7eap | RHSA-2026:53644 |
| Red Hat Jboss Enterprise Application Platform Els 7 | eap7-undertow | 2.2.40-2.SP3_redhat_00001.1.el7eap | RHSA-2026:53644 |
| Red Hat Jboss Enterprise Application Platform Els 7 | eap7-wildfly +4 | 7.4.25-2.GA_redhat_00001.1.el7eap | RHSA-2026:53644 |
| Red Hat JBoss EAP 8 | eap8-eap-product-conf-parent +1 | 801.7.1-1.GA_redhat_00001.1.el8eap | RHSA-2026:49700 |
| Red Hat JBoss EAP 8 | eap8-jose4j | 0.9.6-2.redhat_00002.1.el8eap | RHSA-2026:49700 |
| Red Hat JBoss EAP 8 | eap8-netty +14 | 4.1.135-1.Final_redhat_00001.1.el8eap | RHSA-2026:49700 |
| Red Hat JBoss EAP 8 | eap8-wildfly +3 | 8.1.7.1-1.GA_redhat_00004.1.el8eap | RHSA-2026:49700 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | netty | 4.1.135-150200.4.50.1 | SUSE-SU-2026:2802-1 |
| SLES 15 SP7 | netty-tcnative | 2.0.79-150200.3.45.1 | SUSE-SU-2026:2802-1 |
| SLES 15 SP6 | netty-tcnative | 2.0.79-150200.3.45.1 | SUSE-SU-2026:2802-1 |
| SLES 15 SP5 | netty-tcnative | 2.0.79-150200.3.45.1 | SUSE-SU-2026:2802-1 |
| SLES 15 SP4 | netty-tcnative | 2.0.79-150200.3.45.1 | SUSE-SU-2026:2802-1 |
Show 5 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 15 SP6 | netty-tcnative | 2.0.79-150200.3.45.1 | SUSE-SU-2026:2802-1 |
| SLES for SAP 15 SP5 | netty-tcnative | 2.0.79-150200.3.45.1 | SUSE-SU-2026:2802-1 |
| SLES for SAP 15 SP4 | netty-tcnative | 2.0.79-150200.3.45.1 | SUSE-SU-2026:2802-1 |
| SLE HPC 15 SP5 | netty-tcnative | 2.0.79-150200.3.45.1 | SUSE-SU-2026:2802-1 |
| SLE HPC 15 SP4 | netty-tcnative | 2.0.79-150200.3.45.1 | SUSE-SU-2026:2802-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | netty | 4.1.135-1.1 | openSUSE-SU-2026:11033-1 |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | akhq | 0.27.1-r3 | — |
| Wolfi rolling | apache-activemq-artemis | 2.54.0-r5 | — |
| Wolfi rolling | apache-nifi | 2.9.0-r13 | — |
| Wolfi rolling | apache-nifi-registry | 2.9.0-r10 | — |
| Wolfi rolling | apache-pulsar-4.2 | 4.2.2-r3 | — |
| Wolfi rolling | apicurio-registry | 3.3.0-r2 | — |
| Wolfi rolling | cassandra-5.0 | 5.0.8-r6 | — |
| Wolfi rolling | cassandra-reaper | 4.2.4-r2 | — |
| Wolfi rolling | celeborn-0.6 | 0.6.3-r7 | — |
| Wolfi rolling | docker-selenium-base | 4.44.0.20260505-r2 | — |
| Wolfi rolling | docker-selenium-hub +2 | 4.48.0.20260909-r0 | — |
| Wolfi rolling | druid | 37.0.0-r12 | — |
| Wolfi rolling | flyway | 12.8.1-r3 | — |
| Wolfi rolling | infinispan-16.1 | 16.1.4-r3 | — |
| Wolfi rolling | keycloak-26.5 +2 | 26.5.7-r7 | — |
| Wolfi rolling | keycloak-26.6 +2 | 26.6.3-r2 | — |
| Wolfi rolling | kserve-modelmesh | 0.12.0-r35 | — |
| Wolfi rolling | logstash-9.3 +4 | No fix yet | — |
| Wolfi rolling | logstash-9.4 +1 | 9.4.2-r5 | — |
| Wolfi rolling | management-api-for-apache-cassandra-5.0 | 0.1.119-r0 | — |
| Wolfi rolling | neo4j-2026.05 | 2026.05.0-r1 | — |
| Wolfi rolling | opensearch-2 | 2.19.5-r1 | — |
| Wolfi rolling | opensearch-3 +6 | 3.6.0-r7 | — |
| Wolfi rolling | opensearch-3-discovery-ec2 +2 | 3.8.0-r3 | — |
| Wolfi rolling | opensearch-3-security-analytics | 3.8.0-r2 | — |
| Wolfi rolling | selenium-server | 4.44.0-r2 | — |
| Wolfi rolling | solr-10 +1 | 10.0.0-r5 | — |
| Wolfi rolling | sonarqube | 26.8.0.126808-r0 | — |
| Wolfi rolling | spark-4.0-scala-2.13 | 4.0.3-r0 | — |
| Wolfi rolling | spark-4.1-scala-2.13 | 4.1.2-r4 | — |
| Wolfi rolling | strimzi-kafka-operator-kafka-init +6 | 1.0.0-r6 | — |
| Wolfi rolling | tez | 0.10.5-r16 | — |
| Wolfi rolling | thingsboard-tb-node +1 | 4.3.1.2-r4 | — |
| Wolfi rolling | trino +3 | 483-r7 | — |
| Wolfi rolling | trino-plugin-hive +16 | 481-r7 | — |
| Wolfi rolling | wavefront-proxy | 13.9-r18 | — |
| Wolfi rolling | wildfly-openjdk-17 +1 | 40.0.0-r1 | — |
| Wolfi rolling | zipkin +1 | 3.6.1-r10 | — |
| Wolfi rolling | zookeeper-3.9 | 3.9.5-r7 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Maven | io.netty:netty-handler | >= 4.2.0.Final, < 4.2.15.Final | 4.2.15.Final | GHSA-x4gw-5cx5-pgmh |
| Maven | io.netty:netty-handler | < 4.1.135.Final | 4.1.135.Final | GHSA-x4gw-5cx5-pgmh |
Advisories 12
- RHSA-2026:53644 Red Hat Security Advisory: Red Hat JBoss Enterprise Application Platform 7.4.25 security pdate Red Hat Security Advisories (RHSA) · Nov 13, 2026
- WID-SEC-2026-1814 Netty: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 11, 2026
- WID-SEC-2026-3376 Atlassian Bamboo, Bitbucket, Confluence, Fisheye/Crucible, Jira Software und Jira Service Management: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 10, 2026
- WID-SEC-2026-2923 Atlassian Produkte (Bamboo, Bitbucket, Confluence, Crucible, Fisheye, und Jira): Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 8, 2026
- RHSA-2026:76130 Red Hat Security Advisory: Red Hat Single Sign-On 7.6.13 security update on RHEL 9 Red Hat Security Advisories (RHSA) · Oct 20, 2026
- RHSA-2026:76129 Red Hat Security Advisory: Red Hat Single Sign-On 7.6.13 security update on RHEL 8 Red Hat Security Advisories (RHSA) · Oct 20, 2026
- RHSA-2026:76128 Red Hat Security Advisory: Red Hat Single Sign-On 7.6.13 security update on RHEL 7 Red Hat Security Advisories (RHSA) · Oct 20, 2026
- RHSA-2026:49700 Red Hat Security Advisory: Red Hat JBoss Enterprise Application Platform 8.1.7 security update Red Hat Security Advisories (RHSA) · Oct 20, 2026
- WID-SEC-2026-2460 Atlassian Bamboo, Bitbucket, Confluence, Fisheye, Crucible, Jira und Jira Service Management: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 1, 2026
- NCSC-2026-0325 Kwetsbaarheden verholpen in Atlassian producten NCSC-NL (Netherlands) · Aug 24, 2026
- SUSE-SU-2026:2802-1 Security update for netty, netty-tcnative SUSE / openSUSE Security Updates · Jul 9, 2026
- openSUSE-SU-2026:11033-1 netty-4.1.135-1.1 on GA media SUSE / openSUSE Security Updates · Jun 16, 2026