--- id: CVE-2026-59921 title: >- io.netty/netty-codec-http: Netty: CRLF Injection via Multipart Filename in Netty HttpPostRequestEncoder (CVE-2026-59921) summary: >- A flaw was found in Netty's HttpPostRequestEncoder, a widely used Java networking library component responsible for constructing multipart HTTP request bodies. The issue arises because user-supplied filenames and field names are directly e… severity: medium cvss: 5.7 cvssVector: 'CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N' cvssSource: vendor cwe: CWE-93 vendor: Red Hat product: OpenShift Serverless affected: - cryostat 4 - openshift_serverless - amq_broker 7 - amq_clients - build_of_apache_camel_hawtio 4 - build_of_apache_camel_4_for_quarkus 3 - build_of_apache_camel_for_spring_boot 4 - build_of_apicurio_registry 3 - build_of_debezium 3 - build_of_keycloak - build_of_quarkus - data_grid 8 - enterprise_linux_ai_rhel_ai 3 - jboss_enterprise_application_platform 7 - jboss_enterprise_application_platform 8 - jboss_enterprise_application_platform_expansion_pack - openshift_ai_rhoai - openshift_dev_spaces - satellite 6 - single_sign_on 7 - streams_for_apache_kafka 2 - streams_for_apache_kafka 3 - build_of_quarkus 3.27.4.SP3 - build_of_quarkus 3.33.2.SP3 patched: - build_of_quarkus 3.27.4.SP3 - build_of_quarkus 3.33.2.SP3 published: '2026-07-09' updated: '2026-10-20' sourceUpdated: '2026-10-20T04:42:57+00:00' source: CSAF sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-59921.json' references: - url: >- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-59921.json - url: 'https://access.redhat.com/security/cve/CVE-2026-59921' - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2507467' - url: 'https://www.cve.org/CVERecord?id=CVE-2026-59921' - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-59921' - url: 'https://github.com/netty/netty/security/advisories/GHSA-gcjf-9mgh-3p7g' - url: 'https://access.redhat.com/errata/RHSA-2026:47189' - url: 'https://access.redhat.com/errata/RHSA-2026:47172' - url: 'https://github.com/netty/netty/releases/tag/netty-4.1.136.Final' - url: 'https://github.com/netty/netty/releases/tag/netty-4.2.16.Final' - url: 'https://github.com/advisories/GHSA-gcjf-9mgh-3p7g' tags: - csaf - vex - red-hat - ghsa - maven epss: 0.00465 epssPercentile: 0.40112 aliases: - GHSA-gcjf-9mgh-3p7g ecosystem: maven ingestedAt: '2026-07-22T22:06:57.566Z' --- ## Overview A flaw was found in Netty's HttpPostRequestEncoder, a widely used Java networking library component responsible for constructing multipart HTTP request bodies. The issue arises because user-supplied filenames and field names are directly embedded into Content-Disposition MIME headers without any validation or sanitization of CRLF (\r\n) characters. Since MIME headers are delimited by CRLF sequences, an attacker who controls the filename in a multipart upload can inject arbitrary MIME headers into the request body. This may lead to limited Content-Type spoofing or header manipulation against middleware or storage layers processing the request, though the practical impact is constrained by the context in which Netty is deployed. ## Vendor advisories - **RHSA-2026:47189** · Red Hat · fixed in: Red Hat build of Quarkus 3.27.4.SP3 · released 2026-07-29 · [advisory](https://access.redhat.com/errata/RHSA-2026:47189) - **RHSA-2026:47172** · Red Hat · fixed in: Red Hat build of Quarkus 3.33.2.SP3 · released 2026-07-30 · [advisory](https://access.redhat.com/errata/RHSA-2026:47172) - **Red Hat VEX** · Moderate · affected: Cryostat 4, OpenShift Serverless, Red Hat AMQ Broker 7, Red Hat AMQ Clients, Red Hat build of Apache Camel - HawtIO 4, Red Hat build of Apache Camel 4 for Quarkus 3, … · no fix planned: Cryostat 4, OpenShift Serverless, Red Hat AMQ Broker 7, Red Hat AMQ Clients, … · updated 2026-10-20 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-59921.json) **io.netty/netty-codec-http: Netty: CRLF Injection via Multipart Filename in Netty HttpPostRequestEncoder** — rated Moderate by Red Hat. Released 2026-07-09, updated 2026-10-20. Affected: - Cryostat 4 - OpenShift Serverless - Red Hat AMQ Broker 7 - Red Hat AMQ Clients - Red Hat build of Apache Camel - HawtIO 4 - Red Hat build of Apache Camel 4 for Quarkus 3 - Red Hat build of Apache Camel for Spring Boot 4 - Red Hat build of Apicurio Registry 3 - Red Hat build of Debezium 3 - Red Hat Build of Keycloak - Red Hat build of Quarkus - Red Hat Data Grid 8 - Red Hat Enterprise Linux AI (RHEL AI) 3 - Red Hat JBoss Enterprise Application Platform 7 - Red Hat JBoss Enterprise Application Platform 8 - Red Hat JBoss Enterprise Application Platform Expansion Pack - Red Hat OpenShift AI (RHOAI) - Red Hat OpenShift Dev Spaces - Red Hat Satellite 6 - Red Hat Single Sign-On 7 - streams for Apache Kafka 2 - streams for Apache Kafka 3 Fixed: - Red Hat build of Quarkus 3.27.4.SP3 - Red Hat build of Quarkus 3.33.2.SP3 No fix planned: - Cryostat 4 - OpenShift Serverless - Red Hat AMQ Broker 7 - Red Hat AMQ Clients - Red Hat build of Apache Camel - HawtIO 4 - Red Hat build of Apache Camel 4 for Quarkus 3 - Red Hat build of Apache Camel for Spring Boot 4 - Red Hat build of Apicurio Registry 3 - Red Hat build of Debezium 3 - Red Hat Build of Keycloak - Red Hat build of Quarkus - Red Hat Data Grid 8 - Red Hat Enterprise Linux AI (RHEL AI) 3 - Red Hat JBoss Enterprise Application Platform 7 - Red Hat JBoss Enterprise Application Platform 8 - Red Hat JBoss Enterprise Application Platform Expansion Pack - Red Hat OpenShift AI (RHOAI) - Red Hat OpenShift Dev Spaces - Red Hat Satellite 6 - Red Hat Single Sign-On 7 - streams for Apache Kafka 2 - streams for Apache Kafka 3 Not affected: - Red Hat build of Quarkus 3.27.4.SP3 - Red Hat build of Quarkus 3.33.2.SP3 ## Remediation Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258 https://access.redhat.com/errata/RHSA-2026:47189 Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258 https://access.redhat.com/errata/RHSA-2026:47172 Workarounds / mitigations: - Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability. ## Package advisory (CVE-2026-59921) Affected packages: - `io.netty:netty-codec-http >= 4.2.0.Final, < 4.2.16.Final` - `io.netty:netty-codec-http < 4.1.136.Final` Patched in: - `io.netty:netty-codec-http 4.2.16.Final` - `io.netty:netty-codec-http 4.1.136.Final` Source: https://github.com/advisories/GHSA-gcjf-9mgh-3p7g