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Fencer Vulns
medium 6.8

CVE-2026-45673 json

Netty: DNS Cache Poisoning due to Predictable PRNG and Default Static Source Port

published 2026-06-08 5 mo ago modified 2026-09-10 1 mo ago also GHSA-xmv7-r254-6q78 , EUVD-2026-36445

cvss
6.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 25%
public exploits
0
none known

Summary

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, Netty's DNS resolver uses a predictable PRNG for generating DNS transaction IDs and defaults to a static UDP source port. This combination reduces the entropy of DNS queries, enabling DNS Cache Poisoning (Kaminsky attack). Versions 4.1.135.Final and 4.2.15.Final patch the issue.

Patch / fix

  • maven io.netty:netty-resolver-dns 4.1.135.Final, 4.2.15.Final
  • netty netty 4.1.135, 4.2.15
  • netty-tcnative SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +8 more 2.0.79-150200.3.45.1
  • netty SLE Module for Package Hub 15 SP7 4.1.135-150200.4.50.1

suse advisories SUSE-SU-2026:2802-1

  • netty openSUSE Tumbleweed 4.1.135-1.1

opensuse advisories openSUSE-SU-2026:11033-1

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-2026-45673 updated cvss 6.8

netty-resolver-dns: Netty DNS resolver: DNS Cache Poisoning via predictable transaction IDs

  • Red Hat Cryostat 4 netty-resolver-dns 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 Red Hat build of Apache Camel - HawtIO 4 netty-resolver-dns Red Hat build of Apache Camel 4 for Quarkus 3 netty-resolver-dns Red Hat build of Apache Camel for Spring Boot 4 netty-resolver-dns Red Hat build of Apicurio Registry 3 netty-resolver-dns
    +13 more products
    Red Hat build of Debezium 3 netty-resolver-dns Red Hat Build of Keycloak netty-resolver-dns, rhbk-rhel9-operator, rhbk/keycloak-rhel9, rhbk-openshift-rhel9, rhbk/keycloak-rhel9-operator Red Hat Data Grid 8 netty-resolver-dns Red Hat Enterprise Linux AI (RHEL AI) 3 bazel6, bazel7, bazel8 Red Hat Fuse 7 netty-resolver-dns Red Hat JBoss Enterprise Application Platform 7 netty-resolver-dns Red Hat JBoss Enterprise Application Platform 8 netty-resolver-dns Red Hat JBoss Enterprise Application Platform Expansion Pack netty-resolver-dns Red Hat OpenShift AI (RHOAI) rhoai/odh-spark-operator-rhel9, rhoai/odh-trustyai-service-rhel9, rhoai/odh-th06-cpu-torch210-py312-rhel9, rhoai/odh-th06-cpu-torch291-py312-rhel9, rhoai/odh-th06-rocm64-torch291-py312-rhel9, rhoai/odh-th06-cuda130-torch210-py312-rhel9, +1 more Red Hat OpenShift Dev Spaces devspaces/server-rhel9, devspaces/openvsx-rhel9, devspaces/pluginregistry-rhel9, devspaces/multicluster-redirector-rhel9 Red Hat Single Sign-On 7 netty-resolver-dns Red Hat streams for Apache Kafka 2 netty-resolver-dns Red Hat streams for Apache Kafka 3 netty-resolver-dns
    affected: workaround, no fix available “Fix deferred”
  • Red Hat build of Quarkus 3.27.4.SP1 netty-resolver-dns 4.1.135.Final-redhat-00001
    fixed: vendor fix RHSA-2026:26018
  • Red Hat build of Quarkus 3.33.2.SP1 netty-resolver-dns 4.1.135.Final-redhat-00001
    fixed: vendor fix RHSA-2026:26017
  • Red Hat build of Quarkus 3.27.4.SP1 jna 5.8.0, db2 1.21.4, h2 2.3.230, y18n 5.0.8, cliui 8.0.1, guice 5.1.0, +1009 more Red Hat build of Quarkus 3.33.2.SP1 jna 5.8.0, bson 5.6.4, h2 2.4.240, y18n 5.0.8, cliui 8.0.1, guice 5.1.0, +1018 more
    not affected: vulnerable code 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
no
Technical impact
partial
Assessed
4 mo ago

Exploit prediction

0.32% chance of exploitation in the next 30 days, higher than 25% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.8 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N
GitHub 3.1 6.8 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N

Affected packages

ecosystem package affected fixed in
maven io.netty:netty-resolver-dns
>=4.2.0.Final, <4.2.15.Final
<4.1.135.Final
4.2.15.Final
4.1.135.Final

Affected products

  • netty netty

Classification

Weakness
  • CWE-330 Use of Insufficiently Random Values
  • CWE-340 Generation of Predictable Numbers or Identifiers

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.