Netty: WebSockets V07/V08 handshaker missing Connection/Upgrade validation
Priority LOW 28CWE-444Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- High
- Attack requirements
- None
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · None
- Fix status
- Partial Red Hat: 2 fixed, 22 without a fix
Attack profile from CVSS 4.0 · CNA. 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, ab attacker can force WebSocket upgrade via the lax V07 (or V08) handshaker by sending `Sec-WebSocket-Version: 7` and omitting `Connection: Upgrade` / `Upgrade: websocket` headers, completing a protocol switch that a proxy would not recognize as an Upgrade request and enabling HTTP request smuggling / protocol-confusion attacks. This issue has been fixed in versions 4.1.136.Final and 4.2.16.Final.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00439 38th 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
- None
- 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
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| netty | netty | 4.2.0.Final to before 4.2.16.Final; before 4.1.136.Final | 4.2.16.Final, 4.1.136.Final | Patch available | CNA |
| — | io.netty:netty-codec-http (Maven) | 4.2.0.Final to before 4.2.16.Final | 4.2.16.Final | Patch available | GHSA-4mp9-239f-g9hg |
| — | io.netty:netty-codec-http (Maven) | before 4.1.136.Final | 4.1.136.Final | Patch available | GHSA-4mp9-239f-g9hg |
- 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-4mp9-239f-g9hg
- io.netty:netty-codec-http (Maven) Vendor— Affected before 4.1.136.Final Fixed in 4.1.136.Final Patch available GHSA-4mp9-239f-g9hg
Remediation
- Fix · CNA netty (netty) Fixed in 4.2.16.Final, 4.1.136.Final
- Fix · GHSA-4mp9-239f-g9hg io.netty:netty-codec-http (Maven) Fixed in 4.2.16.Final Advisory →
- Fix · GHSA-4mp9-239f-g9hg 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 ImportantRed 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 ImportantRed 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 →
| Product | Status | Plan or fix |
|---|---|---|
| Cryostat 4 | Affected | No fix yet: Fix deferred |
| OpenShift Serverless | Affected | No fix yet: Fix deferred |
| Red Hat AMQ Broker 7 | Affected | No fix yet: Fix deferred |
| Red Hat AMQ Clients | Affected | No fix yet: Fix deferred |
| Red Hat Build of Keycloak | Affected | No fix yet: Fix deferred |
| Red Hat Data Grid 8 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux AI (RHEL AI) 3 | Affected | No fix yet: Fix deferred |
| Red Hat JBoss Enterprise Application Platform 7 | Affected | No fix planned: Out of support scope |
| Red Hat JBoss Enterprise Application Platform 8 | Affected | No fix yet: Fix deferred |
| Red Hat JBoss Enterprise Application Platform Expansion Pack | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift AI (RHOAI) | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Dev Spaces | Affected | No fix yet: Fix deferred |
| Red Hat Satellite 6 | Affected | No fix yet: Fix deferred |
| Red Hat Single Sign-On 7 | Affected | No fix planned: Out of support scope |
| Red Hat build of Apache Camel - HawtIO 4 | Affected | No fix yet: Fix deferred |
| Red Hat build of Apache Camel 4 for Quarkus 3 | Affected | No fix yet: Fix deferred |
| Red Hat build of Apache Camel for Spring Boot 4 | Affected | No fix yet: Fix deferred |
| Red Hat build of Apicurio Registry 3 | Affected | No fix planned: Out of support scope |
| Red Hat build of Debezium 3 | Affected | No fix yet: Fix deferred |
| Red Hat build of Quarkus | Affected | No fix planned: Out of support scope |
| streams for Apache Kafka 2 | Affected | No fix planned: Out of support scope |
| streams for Apache Kafka 3 | Affected | No fix yet: Fix deferred |
| Red Hat build of Quarkus 3.27.4.SP3 | Fixed | RHSA-2026:47189 |
| Red Hat build of Quarkus 3.33.2.SP3 | Fixed | 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
- 2026-10-02 Threatist record created from CVE-2026-59898
- 2026-10-03 Alias added: GHSA-4mp9-239f-g9hg
- 2026-10-20 Affected versions changed · Red Hat
References
More Netty vulnerabilities
- 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
Sources
- CVE-2026-59898 · CVE Program
- CVE-2026-59898 · NVD
- FIRST EPSS
- GHSA-4mp9-239f-g9hg · GitHub Advisory Database · CC BY 4.0
- CVE-2026-59898 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences