{"id":"CVE-2026-100659","revision":"9bcac7e321444db6b98689caee7ee44f","records":[{"revision":"9bcac7e321444db6b98689caee7ee44f","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-100659","aliases":[],"title":"Netty 4.2.0 through 4.2.17 HTTP/3 Request Routing Bypass","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.","state":0,"publishedAt":"2026-09-26T13:23:26.859+00:00","modifiedAt":"2026-09-28T18:17:29.17+00:00","affected":[{"ecosystem":"Vendor product","name":"netty","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"netty\",\n                    \"product\": \"netty\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"packageURL\": \"pkg:maven/io.netty/netty-codec-http3\",\n                    \"versions\": [\n                        {\n                            \"version\": \"4.2.0.Final\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"custom\",\n                            \"lessThan\": \"4.2.18.Final\"\n                        },\n                        {\n                            \"version\": \"4.2.18.Final\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"custom\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 4.0","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","score":6.9,"severity":"MEDIUM"},{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","score":6.5,"severity":"MEDIUM"}],"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-routing-bypass"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-100659","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-100659","identifiers":["CVE-2026-100659"]},"retained":false,"historicalAffected":[]}],"coverage":[]}