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TI-2026-64819 Aliases CVE-2026-100663GHSA-qmrm-mg2w-2mpw

Netty HTTP/1 CONNECT authority-form mistranslated to malformed HTTP/3

Priority HIGH 71CWE-20Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
None · High · None
Fix status
Partial Red Hat: 1 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) from 4.2.2.Final through 4.2.17.Final does not special-case HTTP/1 CONNECT authority-form request-targets when converting HTTP/1 messages to HTTP/3 in HttpConversionUtil.toHttp3Headers. The authority-form target (e.g., "CONNECT trusted.example:443") is parsed as a URI, so its host is emitted as :scheme, :path is set to "/", and the HTTP/1 Host header is used as :authority; if no Host header is present the CONNECT target is dropped. In a Netty-based HTTP/1-to-HTTP/3 proxy or gateway, a remote client can send a CONNECT request whose Host header names a different authority than the request-target, producing a malformed HTTP/3 CONNECT whose tunnel :authority is attacker-controlled. This can bypass tunnel allow-lists, egress policy, backend selection, or audit controls that validate the HTTP/1 CONNECT request-target before forwarding over HTTP/3. The issue is fixed in 4.2.18.Final.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00301 23rd 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
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
nettynetty4.2.2.Final to before 4.2.18.Final4.2.18.FinalPatch availableCNA
  • netty Vendornetty Affected 4.2.2.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.

CPEVersionsRoleVendor
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 ·

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

ProductStatusPlan or fix
Red Hat OpenShift Dev SpacesAffectedNo fix yet
Not affected: 1 product
  • Red Hat OpenShift AI (RHOAI)

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-100663
  2. 2026-10-03 Alias added: GHSA-qmrm-mg2w-2mpw

References

Advisory 1

  • 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