Authority Confusion in Netty's HTTP/3 Codec
CVE-2026-100664

8.7HIGH

Key Information:

Vendor

Netty

Status
Netty
Vendor
CVE Published:
26 September 2026

What is CVE-2026-100664?

The Netty HTTP/3 codec versions 4.2.2.Final through 4.2.17.Final encounter an authority confusion vulnerability. This issue arises when the codec builds the HTTP/3 :authority pseudo-header from the HTTP/1 Host header without properly considering the request-target's authority, leading to potentially conflicting interpretations of this authority in a Netty-based HTTP/1-to-HTTP/3 gateway. As a result, a remote client may manipulate headers to influence validation, authorization, and routing decisions made by components, potentially compromising security controls that depend on RFC-defined request-target authorities. Users are advised to upgrade to version 4.2.18.Final to mitigate this risk.

Affected Version(s)

netty 4.2.2.Final < 4.2.18.Final

netty 4.2.18.Final

References

https://github.com/netty/netty/security/advisories/GHSA-h...
vendor-advisory
https://www.vulncheck.com/advisories/netty-4.2.2-through-...
third-party-advisory

CVSS V4

Score:
8.7
Severity:
HIGH
Confidentiality:
None
Integrity:
High
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

rexpository
.