# CVE-2026-93566: Io.netty/netty-codec-http: netty: http request smuggling due to control characters in the chunk-size line Status: published. Published: 2026-09-18. Updated: 2026-11-06. A flaw was found in Netty. A remote attacker could exploit this by sending a specially crafted HTTP request that includes control characters within the chunk-size line. This bypasses the intended strict validation, allowing the attacker to inject arbitrary HTTP requests. This vulnerability can lead to HTTP request smuggling, potentially resulting in information disclosure or other unauthorized actions. ## Remediation - workaround: See https://github.com/netty/netty/security/advisories/GHSA-rq4j-fc47-9698 for fixed versions and remediation guidance. (source: CNA: redhat) ## Affected products and versions - 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 (keycloak-rhel9-container): ≥ 26.4-29; < * (unaffected, rpm). Source: CNA: redhat - Red Hat / Red Hat build of Keycloak 26.4 (keycloak-rhel9-operator-bundle-container): ≥ 26.4.17-2; < * (unaffected, rpm). Source: CNA: redhat - Red Hat / Red Hat build of Keycloak 26.4 (keycloak-rhel9-operator-container): ≥ 26.4-30; < * (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 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 JBoss Enterprise Application Platform 8 (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: 6.5 (medium); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N; source: CNA: redhat - CVSS 3.1: 6.5 (medium); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N; source: NVD: secalert@redhat.com - CISA KEV: No listing in collected sources - EPSS: 0.48% as of 2026-11-05; percentile 41.51% - SSVC: exploitation none; automatable yes; technical impact partial; source ADP: CISA-ADP - Weaknesses: CWE-1035 ## 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-2026:83612 (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/security/cve/CVE-2026-93566 (CNA: redhat; vdb-entry, x_refsource_REDHAT) - https://bugzilla.redhat.com/show_bug.cgi?id=2536954 (CNA: redhat; issue-tracking, x_refsource_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-2026:83612 (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/security/cve/CVE-2026-93566 (secalert@redhat.com) - https://bugzilla.redhat.com/show_bug.cgi?id=2536954 (secalert@redhat.com) ## Provenance - CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2026-93566; retrieved 2026-11-06; source updated 2026-11-06 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-93566; retrieved 2026-11-06; source updated 2026-11-06 - FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-93566; retrieved 2026-11-06; source updated Not reported Revision: df573cb4eb0e4a932495a44e06c5e02ae38feaabc507322e4a6e5dd2c6fe7c54 Canonical: https://y2.dev/cve/CVE-2026-93566 ## 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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