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TI-2026-36846 Aliases CVE-2026-50020GHSA-hvcg-qmg6-jm4c

Netty's HttpObjectDecoder skips arbitrary initial control characters when only initial CRLF characters are permitted

Priority MEDIUM 63CWE-444Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
None · Low · None
Fix status
Partial Red Hat: 2 fixed, 20 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat.

Summary

Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, before reading the first request-line, `HttpObjectDecoder` skips every byte for which `Character.isISOControl(b)` is `true` (0x00–0x1F and 0x7F) as well as all whitespace. RFC 9112 §2.2 only asks servers to ignore empty CRLF lines preceding the request-line — a carefully scoped robustness allowance intended to handle HTTP/1.0 POST workarounds. Silently absorbing NUL bytes, SOH, STX, and other non-CRLF control characters goes significantly beyond this, and can be exploited for request-boundary confusion in pipelined or multiplexed transports where a front-end component treats those bytes differently. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00232 14th percentileScored 2026-11-07
Fix Partial netty (netty): 4.2.15.Final, 4.1.135.Finalio.netty:netty-codec-http (Maven): 4.2.15.Final, 4.1.135.FinalRed Hat: 2 advisoriesRed Hat: 2 fixed, 20 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 4.2.15.Final; before 4.1.135.Final4.2.15.Final, 4.1.135.FinalPatch availableCNA
—io.netty:netty-codec-http (Maven)4.2.0.Final to before 4.2.15.Final4.2.15.FinalPatch availableGHSA-hvcg-qmg6-jm4c
—io.netty:netty-codec-http (Maven)before 4.1.135.Final4.1.135.FinalPatch availableGHSA-hvcg-qmg6-jm4c
  • netty Vendornetty Affected 4.2.0.Final to before 4.2.15.Final; before 4.1.135.Final Fixed in 4.2.15.Final, 4.1.135.Final Patch available CNA
  • io.netty:netty-codec-http (Maven) Vendor— Affected 4.2.0.Final to before 4.2.15.Final Fixed in 4.2.15.Final Patch available GHSA-hvcg-qmg6-jm4c
  • io.netty:netty-codec-http (Maven) Vendor— Affected before 4.1.135.Final Fixed in 4.1.135.Final Patch available GHSA-hvcg-qmg6-jm4c

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*before 4.1.135; 4.2.0 to before 4.2.15Vulnerablenetty
  • cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:* Versions before 4.1.135; 4.2.0 to before 4.2.15 Vulnerable ·netty

Remediation

  • Fix · CNA netty (netty) Fixed in 4.2.15.Final, 4.1.135.Final
  • Fix · GHSA-hvcg-qmg6-jm4c io.netty:netty-codec-http (Maven) Fixed in 4.2.15.Final Advisory →
  • Fix · GHSA-hvcg-qmg6-jm4c io.netty:netty-codec-http (Maven) Fixed in 4.1.135.Final Advisory →

Red Hat 2 advisories

  • RHSA-2026:26018 Released 2026-06-17 · Red Hat rating Important
    Red Hat build of Quarkus 3.27.4.SP1 security update
    • Red Hat build of Quarkus 3.27.4.SP1 io.netty.netty-codec-haproxy-4.1.135.Final-redhat-00001.jar, io.netty.netty-codec-http-4.1.135.Final-redhat-00001.jar, io.netty.netty-codec-http2-4.1.135.Final-redhat-00001.jar +4
  • RHSA-2026:26017 Released 2026-06-17 · Red Hat rating Important
    Red Hat build of Quarkus 3.33.2.SP1 security update
    • Red Hat build of Quarkus 3.33.2.SP1 io.netty.netty-codec-haproxy-4.1.135.Final-redhat-00001.jar, io.netty.netty-codec-http-4.1.135.Final-redhat-00001.jar, io.netty.netty-codec-http2-4.1.135.Final-redhat-00001.jar +4

Vendor assessments

Red Hat

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

ProductStatusPlan or fix
Cryostat 4AffectedNo fix yet: Fix deferred
OpenShift ServerlessAffectedNo fix yet: Fix deferred
Red Hat AMQ Broker 7AffectedNo fix yet: Fix deferred
Red Hat AMQ ClientsAffectedNo fix yet: Fix deferred
Red Hat Build of KeycloakAffectedNo fix yet: Fix deferred
Red Hat Data Grid 8AffectedNo fix yet: Fix deferred
Red Hat Fuse 7AffectedNo fix yet: Fix deferred
Red Hat JBoss Enterprise Application Platform 7AffectedNo fix yet: Fix deferred
Red Hat JBoss Enterprise Application Platform 8AffectedNo fix yet: Fix deferred
Red Hat JBoss Enterprise Application Platform Expansion PackAffectedNo fix yet: Fix deferred
Red Hat OpenShift AI (RHOAI)AffectedNo fix yet: Fix deferred
Red Hat OpenShift Dev SpacesAffectedNo fix yet: Fix deferred
Red Hat Single Sign-On 7AffectedNo fix yet: Fix deferred
Red Hat build of Apache Camel - HawtIO 4AffectedNo fix yet: Fix deferred
Red Hat build of Apache Camel 4 for Quarkus 3AffectedNo fix yet: Fix deferred
Red Hat build of Apache Camel for Spring Boot 4AffectedNo fix yet: Fix deferred
Red Hat build of Apicurio Registry 3AffectedNo fix yet: Fix deferred
Red Hat build of Debezium 3AffectedNo fix yet: Fix deferred
streams for Apache Kafka 2AffectedNo fix yet: Fix deferred
streams for Apache Kafka 3AffectedNo fix yet: Fix deferred
Red Hat build of Quarkus 3.27.4.SP1Fixed RHSA-2026:26018
Red Hat build of Quarkus 3.33.2.SP1Fixed RHSA-2026:26017
Not affected: 4 products
  • Red Hat Enterprise Linux AI (RHEL AI) 3
  • Red Hat Satellite 6
  • Red Hat build of Quarkus 3.27.4.SP1
  • Red Hat build of Quarkus 3.33.2.SP1

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-50020
  2. 2026-10-03 Alias added: GHSA-hvcg-qmg6-jm4c
  3. 2026-10-20 Affected versions changed · Red Hat

References

Advisory 2

Other 3

  • 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-2026-40973 Netty: Missing CertificateID Validation in OCSP Response Allows Replay Attacks CVSS 3.1CRITICAL 9.1
  • TI-2026-40972 Uncontrolled resource consumption in netty CVSS 3.1HIGH 7.5
See all 92 →

Sources

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