CVE-2026-93573

Io.netty/netty-codec-http: netty split transfer-encoding fields bypass final-chunked validation and enable request smuggling

publishedCWE-444

A flaw was found in Netty's HTTP/1.1 decoder. This vulnerability allows a remote attacker to bypass `Transfer-Encoding` header validation by splitting the `Transfer-Encoding` field across multiple headers, with the last field containing a non-final transfer coding like `gzip` or `deflate`. This bypass can lead to HTTP request smuggling, enabling attackers to bypass security controls, desynchronize request processing, or cause requests to be processed in an unintended context.

Technical severity6.5 mediumCVSS 3.1 · CNA: redhat

Published2026-09-18Source updated 2026-11-06

Collected2026-11-062 attributed sources

Fixes and workarounds

Workaround

See https://github.com/netty/netty/security/advisories/GHSA-3jrc-fchc-59pw for fixed versions and remediation guidance.

Source: CNA: redhat

Affected products and versions

Affected products, source version ranges and reporting authorities
Product	Versions	Authority
Red Hat Build of Debezium 3.6 Red Hat `netty-codec-http` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: unaffected	CNA: redhat
Red Hat build of Keycloak 26.4 Red Hat `keycloak-rhel9-container` https://catalog.redhat.com/software/containers/	≥ 26.4-29; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat build of Keycloak 26.4 Red Hat `keycloak-rhel9-operator-bundle-container` https://catalog.redhat.com/software/containers/	≥ 26.4.17-2; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat build of Keycloak 26.4 Red Hat `keycloak-rhel9-operator-container` https://catalog.redhat.com/software/containers/	≥ 26.4-30; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat build of Keycloak 26.6.8 Red Hat `netty-codec-http` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: unaffected	CNA: redhat
Red Hat build of Quarkus 3.27.5.SP2 Red Hat `netty-codec-http` https://access.redhat.com/jbossnetwork/restricted/listSoftware.html	Range not reported Other versions: unaffected	CNA: redhat
Red Hat build of Quarkus 3.33.3.SP2 Red Hat `netty-codec-http` https://access.redhat.com/jbossnetwork/restricted/listSoftware.html	Range not reported Other versions: unaffected	CNA: redhat
Red Hat AMQ Broker 7 Red Hat `netty-codec-http` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: affected	CNA: redhat
Red Hat AMQ Clients Red Hat `netty-codec-http` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: affected	CNA: redhat
Red Hat build of Apache Camel 4 for Quarkus 3 Red Hat `netty-codec-http` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: affected	CNA: redhat
Red Hat build of Apache Camel for Spring Boot 4 Red Hat `netty-codec-http` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: affected	CNA: redhat
Red Hat build of Apicurio Registry 3 Red Hat `netty-codec-http` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: affected	CNA: redhat
Red Hat Data Grid 8 Red Hat `netty-codec-http` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: affected	CNA: redhat
Red Hat Fuse 7 Red Hat `netty-codec-http` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: unknown	CNA: redhat
Red Hat JBoss Enterprise Application Platform 7 Red Hat `netty-codec-http` https://access.redhat.com/jbossnetwork/restricted/listSoftware.html	Range not reported Other versions: unknown	CNA: redhat
Red Hat JBoss Enterprise Application Platform 8 Red Hat `netty-codec-http` https://access.redhat.com/jbossnetwork/restricted/listSoftware.html	Range not reported Other versions: affected	CNA: redhat
Red Hat Single Sign-On 7 Red Hat `netty-codec-http` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: unknown	CNA: redhat

Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.

CVSS assessments

CVSS scores, vectors and reporting authorities
Version / score	Vector	Authority
3.1 / 6.5 medium	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N`	CNA: redhat

Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

References

https://access.redhat.com/errata/RHSA-2026:69440CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:69470CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:83612CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:95760CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:95761CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/security/cve/CVE-2026-93573CNA: redhat · vdb-entry, x_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2536964CNA: redhat · issue-tracking, x_refsource_REDHAT

For agents and automation

Read public disclosures for free as Markdown or JSON. Compatible browsers also expose native WebMCP tools to search disclosures, read this page, and discover API access.

Use the ontology-linked Cyber API with x402 pay per request, or a Y2 Pro or Elite API key with the intel:cyber scope.

Get an API key Use x402 Connect an agent

Endpoints and access details

https://api.y2.dev/api/v2/cyber/cves
https://api.y2.dev/api/v2/cyber/cves/{cveId}

A workspace owner or admin can create a Pro or Elite API key. Send Authorization: Bearer <Y2_API_KEY> from your trusted agent runtime.

For x402, omit Authorization and read the HTTP 402 payment challenge before signing a retry. Public browser tools do not make payments.

Agent access JSON · OpenAPI · CVE API guide