--- id: CVE-2026-45416 title: >- Netty is a network application framework for development of protocol servers and clients 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, SslClientHelloHandler.decode() reads the 24-bit TLS handshake length and, when the ClientHello do… severity: high cvss: 7.5 cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H' cwe: - CWE-770 vendor: netty product: netty affected: - netty < 4.1.135 - 'netty >= 4.2.0, < 4.2.15' patched: - netty 4.2.15 published: '2026-06-12' updated: '2026-09-18' sourceUpdated: '2026-09-18T13:18:25.647' source: NVD sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-45416' references: - url: 'https://github.com/netty/netty/releases/tag/netty-4.1.135.Final' label: security-advisories@github.com - url: 'https://github.com/netty/netty/releases/tag/netty-4.2.15.Final' label: security-advisories@github.com - url: 'https://github.com/netty/netty/security/advisories/GHSA-x4gw-5cx5-pgmh' label: security-advisories@github.com - url: 'https://access.redhat.com/errata/RHSA-2026:26017' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:26018' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:26586' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:28573' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:34608' 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-2026:41951' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:48151' 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-2026:50085' 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-2026:62260' 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/errata/RHSA-2026:66488' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:66545' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/security/cve/CVE-2026-45416' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2488391' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: >- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-45416.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-2026-45416' - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-45416' - url: 'https://access.redhat.com/errata/RHSA-2026:69459' tags: - nvd - cve.org - csaf - vex - red-hat epss: 0.00921 epssPercentile: 0.58256 ssvc: exploitation: none automatable: 'yes' technicalImpact: partial timestamp: '2026-06-12T15:06:59.768657Z' ingestedAt: '2026-07-03T14:03:37.092Z' --- ## Overview 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 - `netty < 4.1.135` - `netty >= 4.2.0, < 4.2.15` ## Remediation Upgrade past the affected range: - `netty 4.2.15` ## 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-2026:48151** · Red Hat · fixed in: Cryostat 4 on RHEL 9 · released 2026-07-29 · [advisory](https://access.redhat.com/errata/RHSA-2026:48151) - **RHSA-2026:26586** · Red Hat · fixed in: Red Hat Build of Apache Camel 3.33 for Quarkus 3.33.2.SP1 · released 2026-06-17 · [advisory](https://access.redhat.com/errata/RHSA-2026:26586) - **RHSA-2026:41951** · Red Hat · fixed in: Red Hat Data Grid 8.6.2 · released 2026-07-20 · [advisory](https://access.redhat.com/errata/RHSA-2026:41951) - **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-2026:50085** · Red Hat · fixed in: Red Hat JBoss Enterprise Application Platform 8.1 · released 2026-08-04 · [advisory](https://access.redhat.com/errata/RHSA-2026:50085) - **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-2026:28573** · Red Hat · fixed in: Red Hat Offline Knowledge Portal 1.2.4 · released 2026-06-23 · [advisory](https://access.redhat.com/errata/RHSA-2026:28573) - **RHSA-2026:62260** · Red Hat · fixed in: Red Hat OpenShift Dev Spaces 3.30 · released 2026-09-01 · [advisory](https://access.redhat.com/errata/RHSA-2026:62260) - **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) - **Red Hat VEX** · Important · affected: OpenShift Serverless, Red Hat build of Apache Camel - HawtIO 4, Red Hat build of Apache Camel 4 for Quarkus 3, Red Hat build of Apicurio Registry 3, Red Hat build of Debezium 3, Red Hat Build of Keycloak, … · no fix planned: Red Hat build of Debezium 3, Red Hat Fuse 7, OpenShift Serverless, Red Hat build of Apache Camel - HawtIO 4, … · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-45416.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-2026:66545** · Red Hat · fixed in: Red Hat AMQ Broker 7.13.6 · released 2026-09-10 · [advisory](https://access.redhat.com/errata/RHSA-2026:66545) - **RHSA-2026:66488** · Red Hat · fixed in: Red Hat AMQ Broker 7.14.1 · released 2026-09-10 · [advisory](https://access.redhat.com/errata/RHSA-2026:66488) - **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) - **RHSA-2026:69459** · Red Hat · fixed in: AMQ Clients 2026.Q3 · released 2026-09-21 · [advisory](https://access.redhat.com/errata/RHSA-2026:69459)