{"schema":"threatline.record/2","record":{"id":"CVE-2026-100663","aliases":["GHSA-jgph-cgq3-c627"],"summary":"Netty HTTP/1 CONNECT authority-form mistranslated to malformed HTTP/3","details":"Netty's HTTP/3 codec (io.netty:netty-codec-http3) from 4.2.2.Final through 4.2.17.Final does not special-case HTTP/1 CONNECT authority-form request-targets when converting HTTP/1 messages to HTTP/3 in HttpConversionUtil.toHttp3Headers. The authority-form target (e.g., \"CONNECT trusted.example:443\") is parsed as a URI, so its host is emitted as :scheme, :path is set to \"/\", and the HTTP/1 Host header is used as :authority; if no Host header is present the CONNECT target is dropped. In a Netty-based HTTP/1-to-HTTP/3 proxy or gateway, a remote client can send a CONNECT request whose Host header names a different authority than the request-target, producing a malformed HTTP/3 CONNECT whose tunnel :authority is attacker-controlled. This can bypass tunnel allow-lists, egress policy, backend selection, or audit controls that validate the HTTP/1 CONNECT request-target before forwarding over HTTP/3. The issue is fixed in 4.2.18.Final.","categories":["Frameworks"],"product":"netty","vendor":"netty","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-100663","source_modified_at":"2026-09-28T18:48:51.788Z","fetched_at":"2026-10-23T18:52:38.922436Z","product":"netty","vendor":"netty","versions":[{"version":"4.2.2.Final","status":"affected","versionType":"custom","lessThan":"4.2.18.Final"},{"version":"4.2.18.Final","status":"unaffected","versionType":"custom"}],"defaultStatus":"unaffected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-100663","source_modified_at":"2026-09-28T18:48:51.788Z","fetched_at":"2026-10-23T18:52:38.922436Z","package":{"name":"netty","ecosystem":null},"version":"4.2.18.Final","basis":"first unaffected version stated in the CVE record"}],"cvss":8.7,"severity":"High","kev":{"listed":false},"epss":{"probability":0.00301,"percentile":0.21678,"score_date":"2026-10-23"},"published_at":"2026-09-26T13:23:29.751Z","modified_at":"2026-09-28T18:48:51.788Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-100663","fetched_at":"2026-10-23T18:52:38.922436Z","source_modified_at":"2026-09-28T18:48:51.788Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-100663","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://github.com/netty/netty/security/advisories/GHSA-jgph-cgq3-c627","tags":["vendor-advisory"]},{"source":"CVE List","url":"https://www.vulncheck.com/advisories/netty-http-1-connect-authority-form-mistranslated-to-malformed-http-3","tags":["third-party-advisory"]}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","cvss_source":"CVE List","ssvc":{"exploitation":"poc","automatable":"no","technical_impact":"partial","assessed_at":"2026-09-28T18:48:08.213536Z"},"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-09-28T18:48:51.788Z","content_hash":"f3f58e82411788b5eccecb361e56441b2679427d24ec753539d81e149dfafb99"}}