{"id":"CVE-2026-100659","title":"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 th…","summary":"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 th…","severity":"medium","cvss":6.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","cwe":["CWE-444"],"vendor":"netty","product":"netty","affected":["netty >= 4.2.0.Final < 4.2.18.Final"],"published":"2026-09-26","updated":"2026-09-28","sourceUpdated":"2026-09-28T19:16:45.480","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-100659","references":[{"url":"https://github.com/netty/netty/security/advisories/GHSA-q9pg-8h3j-8hvm","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/netty-4.2.0-through-4.2.18-http-3-request-routing-bypass","label":"disclosure@vulncheck.com"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-100659.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-100659"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2541874"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-100659"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-100659"}],"tags":["nvd","cve.org","csaf","vex","red-hat"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-09-28T18:16:52.799456Z"},"ingestedAt":"2026-09-26T13:33:20.915Z","epss":0.00236,"epssPercentile":0.145,"slug":"CVE-2026-100659","body":"## Overview\n\nNetty'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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat OpenShift AI (RHOAI), Red Hat OpenShift Dev Spaces · no fix planned: Red Hat OpenShift AI (RHOAI), Red Hat OpenShift Dev Spaces · updated 2026-10-01 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-100659.json)","depth":"sunlit","depthScore":36,"depthScoreParts":{"impact":35.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}