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TI-2026-42729 Aliases CVE-2026-59921GHSA-gcjf-9mgh-3p7g

Netty: CRLF Injection via Multipart Filename in Netty HttpPostRequestEncoder

Priority MEDIUM 62CWE-93Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
None · High · None
Fix status
Partial Red Hat: 2 fixed, 22 without a fix

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

Summary

Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.136.Final and 4.2.16.Final, HttpPostRequestEncoder constructs multipart HTTP request bodies by directly concatenating user-supplied filenames and field names into Content-Disposition MIME headers without validating or sanitizing CRLF characters (\r\n). Since MIME headers are delimited by CRLF, an attacker who controls the filename can inject arbitrary MIME headers into the multipart body part. The root cause is that neither the encoder nor the FileUpload implementations' setFilename() methods, which only check for null, neutralize CRLF characters before the filename is embedded into the header. This issue has been fixed in versions 4.1.136.Final and 4.2.16.Final.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00465 40th percentileScored 2026-11-07
Fix Partial netty (netty): 4.2.16.Final, 4.1.136.Finalio.netty:netty-codec-http (Maven): 4.2.16.Final, 4.1.136.FinalRed Hat: 2 advisoriesRed Hat: 2 fixed, 22 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
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 4.2.16.Final; before 4.1.136.Final4.2.16.Final, 4.1.136.FinalPatch availableCNA
—io.netty:netty-codec-http (Maven)4.2.0.Final to before 4.2.16.Final4.2.16.FinalPatch availableGHSA-gcjf-9mgh-3p7g
—io.netty:netty-codec-http (Maven)before 4.1.136.Final4.1.136.FinalPatch availableGHSA-gcjf-9mgh-3p7g
  • netty Vendornetty Affected 4.2.0.Final to before 4.2.16.Final; before 4.1.136.Final Fixed in 4.2.16.Final, 4.1.136.Final Patch available CNA
  • io.netty:netty-codec-http (Maven) Vendor— Affected 4.2.0.Final to before 4.2.16.Final Fixed in 4.2.16.Final Patch available GHSA-gcjf-9mgh-3p7g
  • io.netty:netty-codec-http (Maven) Vendor— Affected before 4.1.136.Final Fixed in 4.1.136.Final Patch available GHSA-gcjf-9mgh-3p7g

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*before 4.1.136; 4.2.0 to before 4.2.16Vulnerablenetty
  • cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:* Versions before 4.1.136; 4.2.0 to before 4.2.16 Vulnerable ·netty

Remediation

  • Fix · CNA netty (netty) Fixed in 4.2.16.Final, 4.1.136.Final
  • Fix · GHSA-gcjf-9mgh-3p7g io.netty:netty-codec-http (Maven) Fixed in 4.2.16.Final Advisory →
  • Fix · GHSA-gcjf-9mgh-3p7g io.netty:netty-codec-http (Maven) Fixed in 4.1.136.Final Advisory →

Red Hat 2 advisories

  • RHSA-2026:47172 Released 2026-07-30 · Red Hat rating Important
    Red Hat build of Quarkus 3.33.2.SP3 security update
    • Red Hat build of Quarkus 3.33.2.SP3 io.netty.netty-codec-haproxy-4.1.136.Final-redhat-00001.jar, io.netty.netty-codec-http-4.1.136.Final-redhat-00001.jar, io.netty.netty-codec-http2-4.1.136.Final-redhat-00001.jar +3
  • RHSA-2026:47189 Released 2026-07-29 · Red Hat rating Important
    Red Hat build of Quarkus 3.27.4.SP3 security update
    • Red Hat build of Quarkus 3.27.4.SP3 io.netty.netty-codec-haproxy-4.1.136.Final-redhat-00001.jar, io.netty.netty-codec-http-4.1.136.Final-redhat-00001.jar, io.netty.netty-codec-http2-4.1.136.Final-redhat-00001.jar +3

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 Enterprise Linux AI (RHEL AI) 3AffectedNo 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 Satellite 6AffectedNo 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
Red Hat build of QuarkusAffectedNo 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.SP3Fixed RHSA-2026:47189
Red Hat build of Quarkus 3.33.2.SP3Fixed RHSA-2026:47172
Not affected: 2 products
  • Red Hat build of Quarkus 3.27.4.SP3
  • Red Hat build of Quarkus 3.33.2.SP3

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-59921
  2. 2026-10-03 Alias added: GHSA-gcjf-9mgh-3p7g
  3. 2026-10-16 Affected versions changed · Red Hat
  4. 2026-10-20 Affected versions changed · Red Hat

References

Advisory 1

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