HTTP/3 Request Routing Bypass in Netty by VMWare
CVE-2026-100659

6.9MEDIUM

Key Information:

Vendor

Netty

Status
Netty
Vendor
CVE Published:
26 September 2026

What is CVE-2026-100659?

The Netty HTTP/3 codec fails to enforce critical header matching requirements, permitting a remote unauthenticated peer to exploit routing and access control inconsistencies. By submitting HEADERS frames with mismatched values in the :authority pseudo-header and the host header, an attacker can bypass standard authority checks, leading to potential security risks and misrouted traffic. This flaw affects multiple versions and has been mitigated in version 4.2.18.Final.

Affected Version(s)

netty 4.2.0.Final < 4.2.18.Final

netty 4.2.18.Final

References

https://github.com/netty/netty/security/advisories/GHSA-q...
vendor-advisory
https://www.vulncheck.com/advisories/netty-4.2.0-through-...
third-party-advisory

CVSS V4

Score:
6.9
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
Low
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

violetagg
.