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.

Project Subscriptions

Vendors Products
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Mon, 28 Sep 2026 19:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Sun, 27 Sep 2026 16:45:00 +0000

Type Values Removed Values Added
Title Netty 4.2.0 through 4.2.18 HTTP/3 Request Routing Bypass Netty 4.2.0 through 4.2.17 HTTP/3 Request Routing Bypass

Sun, 27 Sep 2026 12:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Moderate


Sat, 26 Sep 2026 13:30:00 +0000

Type Values Removed Values Added
Description 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.
Title Netty 4.2.0 through 4.2.18 HTTP/3 Request Routing Bypass
First Time appeared Netty
Netty netty
Weaknesses CWE-444
CPEs cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*
Vendors & Products Netty
Netty netty
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N'}

cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N'}


Projects

Sign in to view the affected projects.

cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-09-28T18:17:29.170Z

Reserved: 2026-09-26T02:33:59.039Z

Link: CVE-2026-100659

cve-icon Vulnrichment

Updated: 2026-09-28T18:17:03.491Z

cve-icon NVD

Status : Deferred

Published: 2026-09-26T14:16:48.830

Modified: 2026-09-28T19:16:45.480

Link: CVE-2026-100659

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-09-26T13:23:26Z

Links: CVE-2026-100659 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-09-26T15:45:14Z

Weaknesses