# CVE-2026-93488: Io.netty/netty-codec-http: netty: denial of service via unbounded concurrent spdy streams Status: published. Published: 2026-09-18. Updated: 2026-11-06. A flaw was found in Netty. SpdySessionHandler accepts an unlimited number of concurrent remote-initiated streams because localConcurrentStreams defaults to Integer.MAX_VALUE and the handler provides no API to change it. A remote peer can open a SPDY connection and send a large number of SYN_STREAM frames with FLAG_FIN=0, causing unbounded heap and direct memory allocation that can lead to JVM OutOfMemoryError and a denial of service. ## 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: 0.80% as of 2026-11-06; percentile 56.74% - 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-2026-93488 (CNA: redhat; vdb-entry, x_refsource_REDHAT) - https://bugzilla.redhat.com/show_bug.cgi?id=2536887 (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-2026-93488 (secalert@redhat.com) - https://bugzilla.redhat.com/show_bug.cgi?id=2536887 (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-2026-93488; retrieved 2026-11-06; source updated 2026-11-06 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-93488; retrieved 2026-11-06; source updated 2026-11-06 - FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-93488; retrieved 2026-11-06; source updated Not reported Revision: b26e83c6545f58793ea4e85578150b0858033d6a94f0cec5e37c295019b333c5 Canonical: https://y2.dev/cve/CVE-2026-93488 ## 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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