Skip to content
Fencer Vulns
high 7.5

CVE-2026-42577 json

Netty: epoll transport denial of service via RST on half-closed TCP connection

published 2026-05-06 6 mo ago modified 2026-09-10 1 mo ago also EUVD-2026-30120 , GHSA-rwm7-x88c-3g2p

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 35%
public exploits
0
none known

Summary

Netty is an asynchronous, event-driven network application framework. From 4.2.0.Final to 4.2.13.Final , Netty's epoll transport fails to detect and close TCP connections that receive a RST after being half-closed, leading to stale channels that are never cleaned up and, in some code paths, a 100% CPU busy-loop in the event loop thread. This vulnerability is fixed in 4.2.13.Final.

Patch / fix

  • maven io.netty:netty-transport-classes-epoll 4.2.13.Final
  • io.netty netty-transport-native-epoll 4.2.13.Final
  • netty netty 4.2.13.Final

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-2026-42577 updated cvss 7.5

io.netty/netty-transport-native-epoll: Netty: Denial of Service due to improper handling of half-closed TCP connections

  • Red Hat Cryostat 4 cryostat/cryostat-rhel9 Red Hat build of Apache Camel 4 for Quarkus 3 netty-transport-native-epoll 4.1.137.Final-redhat-00001 Red Hat build of Apache Camel for Spring Boot 4 netty-transport-native-epoll 4.1.137.Final-redhat-00001 Red Hat build of Debezium 3 netty-transport-native-epoll 4.1.137.Final-redhat-00001 Red Hat Build of Keycloak rhbk/keycloak-rhel9, netty-transport-native-epoll 4.1.137.Final-redhat-00001 Red Hat Enterprise Linux AI (RHEL AI) 3 bazel6 6.5.0-2.el9ai, bazel7 7.7.1-1.el9ai, bazel8 8.6.0-1.el9ai
    affected: no fix available
  • Red Hat Fuse 7 netty-transport-native-epoll 4.1.137.Final-redhat-00001 Red Hat JBoss Enterprise Application Platform 7 jboss-eap-7/eap74-els-openjdk8-openshift-rhel8, jboss-eap-7/eap74-els-openjdk11-openshift-rhel8, jboss-eap-7/eap74-els-openjdk17-openshift-rhel8, netty-transport-native-epoll 4.1.137.Final-redhat-00001
    affected: no fix available “Fix deferred”
  • Red Hat Offline Knowledge Portal offline-knowledge-portal/rhokp-rhel9 Red Hat OpenShift AI (RHOAI) rhoai/odh-modelmesh-rhel9, rhoai/odh-spark-operator-rhel9, rhoai/odh-th-torch-cpu-py312-rhel9, rhoai/odh-th-torch-cuda-py312-rhel9, rhoai/odh-th06-cpu-torch210-py312-rhel9, rhoai/odh-th06-cpu-torch291-py312-rhel9, +3 more Red Hat OpenShift Dev Spaces devspaces/openvsx-rhel9, devspaces/pluginregistry-rhel9 Red Hat Satellite 6 candlepin, candlepin-selinux
    affected: no fix available
  • Red Hat Single Sign-On 7 netty-transport-native-epoll 4.1.137.Final-redhat-00001
    affected: no fix available “Fix deferred”
  • Red Hat streams for Apache Kafka 3 netty-transport-native-epoll 4.1.137.Final-redhat-00001
    affected: no fix available
  • Red Hat AMQ Broker 7 netty-transport-native-epoll 4.1.137.Final-redhat-00001 Red Hat AMQ Clients netty-transport-native-epoll 4.1.137.Final-redhat-00001
    not affected: vulnerable code not present
  • Red Hat Data Grid 8 netty-transport-native-epoll 4.1.137.Final-redhat-00001
    not affected: component not present
  • Red Hat JBoss Enterprise Application Platform 8 netty-transport-native-epoll 4.1.137.Final-redhat-00001
    not affected: vulnerable code not present
show 1 more
  • Red Hat JBoss Enterprise Application Platform Expansion Pack netty-transport-native-epoll 4.1.137.Final-redhat-00001
    not affected: component not present

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
5 mo ago

Exploit prediction

0.41% chance of exploitation in the next 30 days, higher than 35% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub 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-transport-classes-epoll
>=4.2.0.Final, <4.2.13.Final
4.2.13.Final

Affected products

  • netty netty

Classification

Weakness
  • CWE-772 Missing Release of Resource after Effective Lifetime

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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.