# CVE-2026-93491: Io.netty/netty-codec-http: netty: denial of service via unbounded httpservercodec http/1.1 pipeline queue Status: published. Published: 2026-09-18. Updated: 2026-11-06. A flaw was found in Netty's HttpServerCodec. A remote, unauthenticated attacker can exploit this vulnerability by pipelining HTTP/1.1 requests on a single connection and withholding reads. This action causes the methodOverflowQueue to grow without limit, leading to unbounded heap memory consumption and a denial of service due to memory exhaustion. ## Remediation - workaround: 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. (source: CNA: redhat) ## Affected products and versions - Red Hat / Red Hat Build of Apache Camel 3.33.3.SP2 (io.netty/netty-codec-http): ≥ 4.1.138.Final-redhat-00001; < * (unaffected, rpm). Source: CNA: redhat - Red Hat / Red Hat Build of Debezium 3.6 (netty-codec-http): Version range not reported. Source: CNA: redhat - Red Hat / Red Hat build of Keycloak 26.4 (rhbk/keycloak-operator-bundle): ≥ 26.4.17-2; < * (unaffected, rpm). Source: CNA: redhat - Red Hat / Red Hat build of Keycloak 26.4 (rhbk/keycloak-rhel9): ≥ 26.4-29; < * (unaffected, rpm). Source: CNA: redhat - Red Hat / Red Hat build of Keycloak 26.4 (rhbk/keycloak-rhel9-operator): ≥ 26.4-30; < * (unaffected, rpm). Source: CNA: redhat - Red Hat / Red Hat build of Keycloak 26.4.17 (netty-codec-http): Version range not reported. Source: CNA: redhat - Red Hat / Red Hat build of Keycloak 26.6 (rhbk/keycloak-operator-bundle): ≥ 26.6.8-2; < * (unaffected, rpm). Source: CNA: redhat - Red Hat / Red Hat build of Keycloak 26.6 (rhbk/keycloak-rhel9): ≥ 26.6-24; < * (unaffected, rpm). Source: CNA: redhat - Red Hat / Red Hat build of Keycloak 26.6 (rhbk/keycloak-rhel9-operator): ≥ 26.6-24; < * (unaffected, rpm). Source: CNA: redhat - Red Hat / Red Hat build of Keycloak 26.6.8 (netty-codec-http): Version range not reported. Source: CNA: redhat - Red Hat / Red Hat build of Quarkus 3.27.5.SP2 (netty-codec-http): Version range not reported. Source: CNA: redhat - Red Hat / Red Hat build of Quarkus 3.33.3.SP2 (netty-codec-http): Version range not reported. Source: CNA: redhat - Red Hat / Red Hat JBoss Enterprise Application Platform 8.1 (netty-codec-http): Version range not reported. Source: CNA: redhat - Red Hat / Red Hat AMQ Broker 7 (netty-codec-http): Version range not reported. Source: CNA: redhat - Red Hat / Red Hat AMQ Clients (netty-codec-http): Version range not reported. Source: CNA: redhat - Red Hat / Red Hat build of Apache Camel 4 for Quarkus 3 (netty-codec-http): Version range not reported. Source: CNA: redhat - Red Hat / Red Hat build of Apache Camel for Spring Boot 4 (netty-codec-http): Version range not reported. Source: CNA: redhat - Red Hat / Red Hat build of Apicurio Registry 3 (netty-codec-http): Version range not reported. Source: CNA: redhat - Red Hat / Red Hat Data Grid 8 (netty-codec-http): Version range not reported. Source: CNA: redhat - Red Hat / Red Hat Fuse 7 (netty-codec-http): Version range not reported. Source: CNA: redhat - Red Hat / Red Hat JBoss Enterprise Application Platform 7 (netty-codec-http): Version range not reported. Source: CNA: redhat - Red Hat / Red Hat Single Sign-On 7 (netty-codec-http): Version range not reported. Source: CNA: redhat ## Severity and prioritization - CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H; source: CNA: redhat - CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H; source: NVD: secalert@redhat.com - CISA KEV: No listing in collected sources - EPSS: 0.73% as of 2026-11-06; percentile 54.58% - SSVC: exploitation none; automatable yes; technical impact partial; source ADP: CISA-ADP - Weaknesses: CWE-770 ## Exploit evidence No exploit evidence in collected sources. This is not proof of no exploitation. ## References - https://access.redhat.com/errata/RHSA-2026:69440 (CNA: redhat; vendor-advisory, x_refsource_REDHAT) - https://access.redhat.com/errata/RHSA-2026:69470 (CNA: redhat; vendor-advisory, x_refsource_REDHAT) - https://access.redhat.com/errata/RHSA-2026:70257 (CNA: redhat; vendor-advisory, x_refsource_REDHAT) - https://access.redhat.com/errata/RHSA-2026:83612 (CNA: redhat; vendor-advisory, x_refsource_REDHAT) - https://access.redhat.com/errata/RHSA-2026:95759 (CNA: redhat; vendor-advisory, x_refsource_REDHAT) - https://access.redhat.com/errata/RHSA-2026:95760 (CNA: redhat; vendor-advisory, x_refsource_REDHAT) - https://access.redhat.com/errata/RHSA-2026:95761 (CNA: redhat; vendor-advisory, x_refsource_REDHAT) - https://access.redhat.com/errata/RHSA-2026:95762 (CNA: redhat; vendor-advisory, x_refsource_REDHAT) - https://access.redhat.com/errata/RHSA-2026:95887 (CNA: redhat; vendor-advisory, x_refsource_REDHAT) - https://access.redhat.com/security/cve/CVE-2026-93491 (CNA: redhat; vdb-entry, x_refsource_REDHAT) - https://bugzilla.redhat.com/show_bug.cgi?id=2536891 (CNA: redhat; issue-tracking, x_refsource_REDHAT) - https://github.com/netty/netty/releases/tag/netty-4.1.138.Final (CNA: redhat) - https://github.com/netty/netty/releases/tag/netty-4.2.18.Final (CNA: redhat) - https://access.redhat.com/errata/RHSA-2026:69440 (secalert@redhat.com) - https://access.redhat.com/errata/RHSA-2026:69470 (secalert@redhat.com) - https://access.redhat.com/errata/RHSA-2026:70257 (secalert@redhat.com) - https://access.redhat.com/errata/RHSA-2026:83612 (secalert@redhat.com) - https://access.redhat.com/errata/RHSA-2026:95759 (secalert@redhat.com) - https://access.redhat.com/errata/RHSA-2026:95760 (secalert@redhat.com) - https://access.redhat.com/errata/RHSA-2026:95761 (secalert@redhat.com) - https://access.redhat.com/errata/RHSA-2026:95762 (secalert@redhat.com) - https://access.redhat.com/errata/RHSA-2026:95887 (secalert@redhat.com) - https://access.redhat.com/security/cve/CVE-2026-93491 (secalert@redhat.com) - https://bugzilla.redhat.com/show_bug.cgi?id=2536891 (secalert@redhat.com) - https://github.com/netty/netty/releases/tag/netty-4.1.138.Final (secalert@redhat.com) - https://github.com/netty/netty/releases/tag/netty-4.2.18.Final (secalert@redhat.com) ## Provenance - CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2026-93491; retrieved 2026-11-06; source updated 2026-11-06 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-93491; retrieved 2026-11-06; source updated 2026-11-06 - FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-93491; retrieved 2026-11-06; source updated Not reported Revision: 32c50fb5f372f74dc85c12733077f8d1a6c9373216fe1246efde427c51fdff5c Canonical: https://y2.dev/cve/CVE-2026-93491 ## Agent and API access Public CVE pages, Markdown, and JSON are free to read without an account or API key. - Public catalog: https://y2.dev/cve/index.json. 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