--- id: CVE-2026-42579 title: 'Netty is an asynchronous, event-driven network application framework' summary: >- Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Netty's DNS codec does not enforce RFC 1035 domain name constraints during either encoding or decoding. This creates a bidirec… severity: high cvss: 7.5 cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N' cwe: - CWE-20 - CWE-400 - CWE-626 - CWE-1286 vendor: netty product: netty affected: - netty < 4.1.133 - 'netty >= 4.2.0, < 4.2.13' patched: - netty 4.2.13 published: '2026-05-13' updated: '2026-09-18' sourceUpdated: '2026-09-18T13:18:19.477' source: NVD sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-42579' references: - url: 'https://github.com/netty/netty/security/advisories/GHSA-cm33-6792-r9fm' label: security-advisories@github.com - url: 'https://access.redhat.com/errata/RHSA-2026:23808' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:24502' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:25123' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:28010' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:36820' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:37390' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:49700' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:49701' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:53644' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:53645' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:53646' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:54435' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:65126' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/security/cve/CVE-2026-42579' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2477217' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://github.com/netty/netty/security/advisories/GHSA-cm33-6792-r9fm' label: 134c704f-9b21-4f2e-91b3-4a467353bcc0 - url: >- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42579.json label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:53806' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://www.cve.org/CVERecord?id=CVE-2026-42579' - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-42579' tags: - nvd - cve.org - exploit-available - csaf - vex - red-hat epss: 0.01006 epssPercentile: 0.61018 exploitAvailable: true ssvc: exploitation: poc automatable: 'yes' technicalImpact: partial timestamp: '2026-05-18T15:39:59.449891Z' ingestedAt: '2026-07-10T01:55:23.218Z' --- ## Overview Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Netty's DNS codec does not enforce RFC 1035 domain name constraints during either encoding or decoding. This creates a bidirectional attack surface: malicious DNS responses can exploit the decoder, and user-influenced hostnames can exploit the encoder. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final. ## Affected - `netty < 4.1.133` - `netty >= 4.2.0, < 4.2.13` ## Remediation Upgrade past the affected range: - `netty 4.2.13` ## Vendor advisories - **RHSA-2026:49700** · Red Hat · fixed in: Red Hat JBoss EAP 8.1 for RHEL 10, Red Hat JBoss EAP 8.1 for RHEL 8, Red Hat JBoss EAP 8.1 for RHEL 9 · released 2026-08-03 · [advisory](https://access.redhat.com/errata/RHSA-2026:49700) - **RHSA-2026:53644** · Red Hat · fixed in: Red Hat JBoss EAP 7.4 ELS for RHEL 7 Server · released 2026-08-11 · [advisory](https://access.redhat.com/errata/RHSA-2026:53644) - **RHSA-2026:28010** · Red Hat · fixed in: Cryostat 4 on RHEL 9 · released 2026-06-22 · [advisory](https://access.redhat.com/errata/RHSA-2026:28010) - **RHSA-2026:53806** · Red Hat · fixed in: Red Hat JBoss Enterprise Application Platform 7.4.25 · released 2026-08-11 · [advisory](https://access.redhat.com/errata/RHSA-2026:53806) - **RHSA-2026:25123** · Red Hat · fixed in: Red Hat OpenShift Dev Spaces 3.28 · released 2026-06-10 · [advisory](https://access.redhat.com/errata/RHSA-2026:25123) - **RHSA-2026:36820** · Red Hat · fixed in: Red Hat OpenShift Dev Spaces 3.29 · released 2026-07-08 · [advisory](https://access.redhat.com/errata/RHSA-2026:36820) - **RHSA-2026:37390** · Red Hat · fixed in: Red Hat build of Apache Camel 4.18.1.P1 for Spring Boot 3.5.16 · released 2026-07-09 · [advisory](https://access.redhat.com/errata/RHSA-2026:37390) - **RHSA-2026:23808** · Red Hat · fixed in: Red Hat build of Quarkus 3.27.4 · released 2026-06-10 · [advisory](https://access.redhat.com/errata/RHSA-2026:23808) - **RHSA-2026:24502** · Red Hat · fixed in: Red Hat build of Quarkus 3.33.2 · released 2026-06-10 · [advisory](https://access.redhat.com/errata/RHSA-2026:24502) - **RHSA-2026:54435** · Red Hat · fixed in: Streams for Apache Kafka 3.2.1 · released 2026-08-12 · [advisory](https://access.redhat.com/errata/RHSA-2026:54435) - **Red Hat VEX** · Important · affected: OpenShift Serverless, Red Hat build of Apicurio Registry 2, Red Hat build of Debezium 3, Red Hat Build of Keycloak, Red Hat build of OptaPlanner 8, Red Hat Data Grid 8, … · no fix planned: Red Hat build of Apicurio Registry 2, Red Hat build of Debezium 3, Red Hat Build of Keycloak, Red Hat Data Grid 8, … · updated 2026-09-17 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42579.json) - **RHSA-2026:65126** · Red Hat · fixed in: Red Hat OpenShift AI 2.25 · released 2026-09-08 · [advisory](https://access.redhat.com/errata/RHSA-2026:65126) - **RHSA-2026:49701** · Red Hat · fixed in: Red Hat JBoss Enterprise Application Platform 8.1.7.GA · released 2026-08-03 · [advisory](https://access.redhat.com/errata/RHSA-2026:49701) - **RHSA-2026:53645** · Red Hat · fixed in: Red Hat JBoss EAP 7.4 ELS for RHEL 8 · released 2026-08-11 · [advisory](https://access.redhat.com/errata/RHSA-2026:53645) - **RHSA-2026:53646** · Red Hat · fixed in: Red Hat JBoss EAP 7.4 ELS for RHEL 9 · released 2026-08-11 · [advisory](https://access.redhat.com/errata/RHSA-2026:53646)