Netty: epoll transport denial of service via RST on half-closed TCP connection
Priority LOW 39CWE-772Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 14 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-772.
Summary
Netty is an asynchronous, event-driven network application framework. From 4.2.0.Final to 4.2.13.Final , Netty's epoll transport fails to detect and close TCP connections that receive a RST after being half-closed, leading to stale channels that are never cleaned up and, in some code paths, a 100% CPU busy-loop in the event loop thread. This vulnerability is fixed in 4.2.13.Final.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00408 35th percentileScored 2026-11-07
Fix Partial netty (netty): 4.2.13.Finalio.netty:netty-transport-classes-epoll (Maven): 4.2.13.FinalRed Hat: 14 without a fix
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- 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
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| netty | netty | 4.2.0.Final to before 4.2.13.Final | 4.2.13.Final | Patch available | CNA |
| — | io.netty:netty-transport-classes-epoll (Maven) | 4.2.0.Final to before 4.2.13.Final | 4.2.13.Final | Patch available | GHSA-rwm7-x88c-3g2p |
- netty Vendornetty Affected 4.2.0.Final to before 4.2.13.Final Fixed in 4.2.13.Final Patch available CNA
- io.netty:netty-transport-classes-epoll (Maven) Vendor— Affected 4.2.0.Final to before 4.2.13.Final Fixed in 4.2.13.Final Patch available GHSA-rwm7-x88c-3g2p
Remediation
- Fix · CNA netty (netty) Fixed in 4.2.13.Final
- Fix · GHSA-rwm7-x88c-3g2p io.netty:netty-transport-classes-epoll (Maven) Fixed in 4.2.13.Final Advisory →
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Cryostat 4 | Affected | No fix yet |
| Red Hat Build of Keycloak | Affected | No fix yet |
| Red Hat Enterprise Linux AI (RHEL AI) 3 | Affected | No fix yet |
| Red Hat Fuse 7 | Affected | No fix yet: Fix deferred |
| Red Hat JBoss Enterprise Application Platform 7 | Affected | No fix yet: Fix deferred |
| Red Hat Offline Knowledge Portal | Affected | No fix yet |
| Red Hat OpenShift AI (RHOAI) | Affected | No fix yet |
| Red Hat OpenShift Dev Spaces | Affected | No fix yet |
| Red Hat Satellite 6 | Affected | No fix yet |
| Red Hat Single Sign-On 7 | Affected | No fix yet: Fix deferred |
| Red Hat build of Apache Camel 4 for Quarkus 3 | Affected | No fix yet |
| Red Hat build of Apache Camel for Spring Boot 4 | Affected | No fix yet |
| Red Hat build of Debezium 3 | Affected | No fix yet |
| streams for Apache Kafka 3 | Affected | No fix yet |
Not affected: 5 products
- Red Hat AMQ Broker 7
- Red Hat AMQ Clients
- Red Hat Data Grid 8
- Red Hat JBoss Enterprise Application Platform 8
- Red Hat JBoss Enterprise Application Platform Expansion Pack
Timeline
- 2026-10-02 Threatist record created from CVE-2026-42577
- 2026-10-03 Alias added: GHSA-rwm7-x88c-3g2p
- 2026-10-25 Priority changed: MEDIUM → LOW
- 2026-11-03 Affected versions changed · Red Hat
- 2026-11-03 CVSS score added · Red Hat
- 2026-11-04 Affected versions changed · Red Hat
- 2026-11-04 Affected versions changed · Red Hat
- 2026-11-05 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-2026-42577 · CVE Program
- CVE-2026-42577 · NVD
- FIRST EPSS
- GHSA-rwm7-x88c-3g2p · GitHub Advisory Database · CC BY 4.0
- CVE-2026-42577 · 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