Vulnerability 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.
CVSS Score
MEDIUM
Related Weaknesses (CWE)
References
- https://github.com/netty/netty/security/advisories/GHSA-q9pg-8h3j-8hvm
- https://www.vulncheck.com/advisories/netty-4.2.0-through-4.2.18-http-3-request-r
FAQ
What is CVE-2026-100659?
CVE-2026-100659 is a vulnerability with a CVSS score of 6.5 (MEDIUM). 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 head...
How severe is CVE-2026-100659?
CVE-2026-100659 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-100659?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.