TI-2026-64815 Aliases CVE-2026-100659 GHSA-7j27-hw46-m8m8

Netty 4.2.0 through 4.2.17 HTTP/3 Request Routing Bypass

LOW 36CWE-444Published 2026-09-26 · Updated 2026-09-28

Key facts

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

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

Summary

Netty's HTTP/3 codec (io.netty:netty-codec-http3) in versions 4.2.0.Final through 4.2.17.Final does not enforce the RFC 9114 requirement that the :authority pseudo-header field and a literal host header field, when both present, carry the same value. A remote unauthenticated peer can send a single HEADERS frame containing both fields with differing, attacker-controlled values; the request is accepted and delivered to the application with two conflicting authorities, allowing routing, virtual-host, and access-control decisions to be bypassed when different components in the request path consult different fields. This issue is fixed in 4.2.18.Final.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00236 14th percentileScored 2026-11-07

Fix Partial netty (netty): 4.2.18.FinalRed Hat: 2 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 4.2.18.Final	4.2.18.Final	Patch available	CNA

netty Vendornetty Affected 4.2.0.Final to before 4.2.18.Final Fixed in 4.2.18.Final Patch available CNA

CPE names Threatist (inferred) · 1

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

CPE	Versions	Role	Vendor
cpe:2.3:a:netty:netty::::::::	—	—	netty

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

Remediation

Fix · CNA netty (netty) Fixed in 4.2.18.Final

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

Release · 2026-09-26
netty 4.2.18.Final
7 records Highest priority Priority HIGH 4 HIGH, 2 MEDIUM, 1 LOW
Other records, highest priority first
- TI-2026-64821 Netty 4.2.11 through 4.2.17 QUIC Hostname Verification BypassPriority HIGH 77
- TI-2026-64818 Netty HTTP/3 QPACK encoder-stream unbounded memory exhaustion DoSPriority HIGH 77
- TI-2026-64816 Netty before 4.2.18.Final QpackEncoder Unbounded Memory RetentionPriority HIGH 77
Show all 7 records →

Vendor assessments

Red Hat

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

Product	Status	Plan or fix
Red Hat OpenShift AI (RHOAI)	Affected	No fix yet: Fix deferred
Red Hat OpenShift Dev Spaces	Affected	No fix yet: Fix deferred

Timeline

2026-10-02 Threatist record created from CVE-2026-100659
2026-10-03 Alias added: GHSA-7j27-hw46-m8m8

References

Advisory 1

GitHub Security Advisory (GHSA-q9pg-8h3j-8hvm)

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