{"id":"GHSA-c69g-56f8-xwqj","summary":"Netty: [codec-http2] Lack of Host Header Deduplication in HTTP/2→HTTP/1.x Translation Leads to Request Routing Bypass","details":"Netty's HTTP/2-to-HTTP/1.x translation layer (`Http2StreamFrameToHttpObjectCodec` and `InboundHttp2ToHttpAdapter`) fails to deduplicate or validate `Host` headers when an HTTP/2 client supplies both the `:authority` pseudo-header and a literal `host` header in a single HEADERS frame. The translator maps `:authority` to `Host` and separately copies the literal `host` header, producing an `HttpRequest` object containing two `Host` headers with attacker-controlled differing values.","aliases":["CVE-2026-59900"],"modified":"2026-07-22T23:25:39.551889Z","published":"2026-07-22T21:49:28Z","database_specific":{"github_reviewed_at":"2026-07-22T21:49:28Z","nvd_published_at":null,"cwe_ids":["CWE-444"],"severity":"MODERATE","github_reviewed":true},"references":[{"type":"WEB","url":"https://github.com/netty/netty/security/advisories/GHSA-c69g-56f8-xwqj"},{"type":"PACKAGE","url":"https://github.com/netty/netty"},{"type":"WEB","url":"https://github.com/netty/netty/releases/tag/netty-4.1.136.Final"},{"type":"WEB","url":"https://github.com/netty/netty/releases/tag/netty-4.2.16.Final"}],"affected":[{"package":{"name":"io.netty:netty-codec-http2","ecosystem":"Maven","purl":"pkg:maven/io.netty/netty-codec-http2"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.2.0.Final"},{"fixed":"4.2.16.Final"}]}],"versions":["4.2.0.Final","4.2.1.Final","4.2.10.Final","4.2.11.Final","4.2.12.Final","4.2.13.Final","4.2.14.Final","4.2.15.Final","4.2.2.Final","4.2.3.Final","4.2.4.Final","4.2.5.Final","4.2.6.Final","4.2.7.Final","4.2.8.Final","4.2.9.Final"],"database_specific":{"last_known_affected_version_range":"\u003c= 4.2.15.Final","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-c69g-56f8-xwqj/GHSA-c69g-56f8-xwqj.json"}},{"package":{"name":"io.netty:netty-codec-http2","ecosystem":"Maven","purl":"pkg:maven/io.netty/netty-codec-http2"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.1.136.Final"}]}],"versions":["4.1.0.Beta4","4.1.0.Beta5","4.1.0.Beta6","4.1.0.Beta7","4.1.0.Beta8","4.1.0.CR1","4.1.0.CR2","4.1.0.CR3","4.1.0.CR4","4.1.0.CR5","4.1.0.CR6","4.1.0.CR7","4.1.0.Final","4.1.1.Final","4.1.10.Final","4.1.100.Final","4.1.101.Final","4.1.102.Final","4.1.103.Final","4.1.104.Final","4.1.105.Final","4.1.106.Final","4.1.107.Final","4.1.108.Final","4.1.109.Final","4.1.11.Final","4.1.110.Final","4.1.111.Final","4.1.112.Final","4.1.113.Final","4.1.114.Final","4.1.115.Final","4.1.116.Final","4.1.117.Final","4.1.118.Final","4.1.119.Final","4.1.12.Final","4.1.120.Final","4.1.121.Final","4.1.122.Final","4.1.123.Final","4.1.124.Final","4.1.125.Final","4.1.126.Final","4.1.127.Final","4.1.128.Final","4.1.129.Final","4.1.13.Final","4.1.130.Final","4.1.131.Final","4.1.132.Final","4.1.133.Final","4.1.134.Final","4.1.135.Final","4.1.14.Final","4.1.15.Final","4.1.16.Final","4.1.17.Final","4.1.18.Final","4.1.19.Final","4.1.2.Final","4.1.20.Final","4.1.21.Final","4.1.22.Final","4.1.23.Final","4.1.24.Final","4.1.25.Final","4.1.26.Final","4.1.27.Final","4.1.28.Final","4.1.29.Final","4.1.3.Final","4.1.30.Final","4.1.31.Final","4.1.32.Final","4.1.33.Final","4.1.34.Final","4.1.35.Final","4.1.36.Final","4.1.37.Final","4.1.38.Final","4.1.39.Final","4.1.4.Final","4.1.40.Final","4.1.41.Final","4.1.42.Final","4.1.43.Final","4.1.44.Final","4.1.45.Final","4.1.46.Final","4.1.47.Final","4.1.48.Final","4.1.49.Final","4.1.5.Final","4.1.50.Final","4.1.51.Final","4.1.52.Final","4.1.53.Final","4.1.54.Final","4.1.55.Final","4.1.56.Final","4.1.57.Final","4.1.58.Final","4.1.59.Final","4.1.6.Final","4.1.60.Final","4.1.61.Final","4.1.62.Final","4.1.63.Final","4.1.64.Final","4.1.65.Final","4.1.66.Final","4.1.67.Final","4.1.68.Final","4.1.69.Final","4.1.7.Final","4.1.70.Final","4.1.71.Final","4.1.72.Final","4.1.73.Final","4.1.74.Final","4.1.75.Final","4.1.76.Final","4.1.77.Final","4.1.78.Final","4.1.79.Final","4.1.8.Final","4.1.80.Final","4.1.81.Final","4.1.82.Final","4.1.83.Final","4.1.84.Final","4.1.85.Final","4.1.86.Final","4.1.87.Final","4.1.88.Final","4.1.89.Final","4.1.9.Final","4.1.90.Final","4.1.91.Final","4.1.92.Final","4.1.93.Final","4.1.94.Final","4.1.95.Final","4.1.96.Final","4.1.97.Final","4.1.98.Final","4.1.99.Final"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-c69g-56f8-xwqj/GHSA-c69g-56f8-xwqj.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N"}]}