TI-2026-64816 Aliases CVE-2026-100660 GHSA-8rpm-pm7h-f5fv

Netty before 4.2.18.Final QpackEncoder Unbounded Memory Retention

HIGH 77CWE-770Published 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: Denial of service
Confidentiality · integrity · availability: None · None · High
Fix status: Partial Red Hat: 1 without a fix

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-770.

Summary

Netty's HTTP/3 codec (io.netty:netty-codec-http3) from 4.2.0.Final through 4.2.17.Final retains unbounded per-stream QPACK encoder state. QpackEncoder stores a queue and a dynamic-table index tracker for every encoded field section that references the QPACK dynamic table, keyed by the peer-controlled QUIC stream ID, and these entries are released only when the remote decoder sends a Section Acknowledgment or Stream Cancellation instruction — not when the HTTP/3 stream completes. There is no limit on the number of tracked streams, field sections, or retained bytes. A remote, unauthenticated HTTP/3 client can advertise a non-zero QPACK dynamic-table capacity, acknowledge the table insertion so the server reuses a dynamically indexed response header, and then omit all mandatory Section Acknowledgments while issuing sequential requests over a single QUIC connection, bypassing concurrent-stream limits and causing unbounded heap growth until the server exhausts memory (denial of service). Fixed in 4.2.18.Final.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00454 39th percentileScored 2026-11-07

Fix Partial netty (netty): 4.2.18.FinalRed Hat: 1 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

Vendor	Product	Affected versions	Fixed in	Status	Source
netty	netty	before 4.2.18.Final	4.2.18.Final	Patch available	CNA

netty Vendornetty Affected 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-2026-64819 Netty HTTP/1 CONNECT authority-form mistranslated to malformed HTTP/3Priority HIGH 71
Show all 7 records →

Vendor assessments

Red Hat

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

Product	Status	Plan or fix
Red Hat OpenShift Dev Spaces	Affected	No fix yet

Not affected: 1 product

Red Hat OpenShift AI (RHOAI)

Timeline

2026-10-02 Threatist record created from CVE-2026-100660
2026-10-03 Alias added: GHSA-8rpm-pm7h-f5fv

References

Advisory 1

GitHub Security Advisory (GHSA-495p-pchh-r4mc)

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