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TI-2026-64822 Aliases CVE-2026-100666GHSA-jq5g-c66v-g3r2

Netty 4.2.0 through 4.2.16 Response Desynchronization via HttpServerCodec

Priority HIGH 70CWE-444Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
Low · Low · Low
Fix status
Partial Red Hat: 3 fixed, 11 without a fix

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat.

Summary

Netty's HttpServerCodec (io.netty:netty-codec-http) in versions 4.2.0.Final through 4.2.16.Final and in versions up to and including 4.1.136.Final pairs each outbound response with an inbound request by calling pollMethod() once per response, including for 1xx informational responses. If a client pipelines an HTTP/1.1 GET carrying an Expect: 100-continue header followed by a HEAD request, the 100 Continue response consumes the queued GET method, so the subsequent 200 OK for the GET is paired with HEAD and its body is dropped, while the following 200 OK for the HEAD request is written with a body. This desynchronizes HTTP parsing on the connection: the GET entity is never delivered and the HEAD response body is interpreted as the GET body, resulting in response splitting and unsafe connection reuse. Fixed in 4.2.17.Final and 4.1.137.Final.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00294 22nd percentileScored 2026-11-07
Fix Partial netty (netty): 4.2.17.Final, 4.1.137.FinalRed Hat: 3 advisoriesRed Hat: 3 fixed, 11 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
nettynetty4.2.0.Final to before 4.2.17.Final4.2.17.FinalPatch availableCNA
nettynettybefore 4.1.137.Final4.1.137.FinalPatch availableCNA
  • netty Vendornetty Affected 4.2.0.Final to before 4.2.17.Final Fixed in 4.2.17.Final Patch available CNA
  • netty Vendornetty Affected before 4.1.137.Final Fixed in 4.1.137.Final Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*——netty
  • cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:* Versions — — ·netty

Remediation

  • Fix · CNA netty (netty) Fixed in 4.2.17.Final
  • Fix · CNA netty (netty) Fixed in 4.1.137.Final

Red Hat 3 advisories

  • RHSA-2026:95887 Released 2026-11-06 · Red Hat rating Important
    Red Hat JBoss Enterprise Application Platform 8.1.9 security update
    • Red Hat JBoss Enterprise Application Platform 8.1
  • RHSA-2026:90321 Released 2026-10-26 · Red Hat rating Critical
    Red Hat OpenShift Dev Spaces 3.31.0 Release.
    • Red Hat OpenShift Dev Spaces 3.31 registry.redhat.io/devspaces/code-rhel9, registry.redhat.io/devspaces/dashboard-rhel9, registry.redhat.io/devspaces/jetbrains-ide-rhel9 +8
  • RHSA-2026:83612 Released 2026-10-15 · Red Hat rating Important
    Red Hat build of Debezium 3.6.3 release
    • Red Hat Build of Debezium 3.6

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Exploit IntelligenceAffectedNo fix yet
OpenShift ServerlessAffectedNo fix yet
Red Hat AMQ ClientsAffectedNo fix yet
Red Hat Build of KeycloakAffectedNo fix yet
Red Hat Data Grid 8AffectedNo fix yet
Red Hat Enterprise Linux AI (RHEL AI) 3AffectedNo fix yet
Red Hat JBoss Enterprise Application Platform 7AffectedNo fix planned: Will not fix
Red Hat OpenShift AI (RHOAI)AffectedNo fix yet
Red Hat Single Sign-On 7AffectedNo fix planned: Will not fix
Red Hat build of Apache Camel for Spring Boot 4AffectedNo fix yet
Red Hat build of Apicurio Registry 3AffectedNo fix yet
Red Hat Build of Debezium 3.6Fixed RHSA-2026:83612
Red Hat JBoss Enterprise Application Platform 8.1Fixed RHSA-2026:95887
Red Hat OpenShift Dev Spaces 3.31Fixed RHSA-2026:90321
Not affected: 8 products
  • Red Hat AMQ Broker 7
  • Red Hat Fuse 7
  • Red Hat JBoss Enterprise Application Platform Expansion Pack
  • Red Hat OpenShift AI (RHOAI)
  • Red Hat OpenShift Dev Spaces 3.31
  • Red Hat Satellite 6
  • Red Hat build of Apache Camel 4 for Quarkus 3
  • Red Hat build of Quarkus

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-100666
  2. 2026-10-03 Alias added: GHSA-jq5g-c66v-g3r2
  3. 2026-10-16 Fix available: RHSA-2026:83612 · Red Hat
  4. 2026-10-16 Fix available: Red Hat Build of Debezium 3.6 · Red Hat
  5. 2026-10-23 Affected versions changed · Red Hat
  6. 2026-10-29 Fix available: Red Hat OpenShift Dev Spaces 3.31 · Red Hat
  7. 2026-10-30 Fix available: RHSA-2026:90321 · Red Hat
  8. 2026-11-06 Fix available: RHSA-2026:95887 · Red Hat
  9. 2026-11-06 Fix available: Red Hat JBoss Enterprise Application Platform 8.1 · Red Hat

References

Advisory 1

  • TI-2023-23979 The HTTP/2 protocol allows a denial of service (server resource consumption) because… KEVCVSS 3.1HIGH 7.5
  • TI-2026-30861 Netty: HTTP/1.0 TE+CL Coexistence Bypasses Smuggling Sanitization CVSS 3.1CRITICAL 9.8
  • TI-2026-30864 Netty: HttpClientCodec response desynchronization CVSS 3.1CRITICAL 9.1
  • TI-2026-30859 Netty: DNS Codec Input Validation Bypass in Netty (Encoder + Decoder) CVSS 3.1CRITICAL 9.1
  • TI-2026-64821 Netty 4.2.11 through 4.2.17 QUIC Hostname Verification Bypass CVSS 4.0HIGH 8.7
  • TI-2026-64818 Netty HTTP/3 QPACK encoder-stream unbounded memory exhaustion DoS CVSS 4.0HIGH 8.7
See all 114 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences