{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-59900","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-07-07T16:40:07.984Z","datePublished":"2026-07-29T17:58:35.543Z","dateUpdated":"2026-07-29T18:07:24.906Z"},"containers":{"cna":{"title":"Netty codec-http2: Lack of Host Header Deduplication in HTTP/2→HTTP/1.x Translation Leads to Request Routing Bypass","problemTypes":[{"descriptions":[{"cweId":"CWE-444","lang":"en","description":"CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')","type":"CWE"}]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"LOW","subIntegrityImpact":"LOW","subAvailabilityImpact":"NONE","baseScore":6.9,"baseSeverity":"MEDIUM","vectorString":"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","version":"4.0"}}],"references":[{"name":"https://github.com/netty/netty/security/advisories/GHSA-c69g-56f8-xwqj","tags":["x_refsource_CONFIRM"],"url":"https://github.com/netty/netty/security/advisories/GHSA-c69g-56f8-xwqj"},{"name":"https://github.com/netty/netty/releases/tag/netty-4.1.136.Final","tags":["x_refsource_MISC"],"url":"https://github.com/netty/netty/releases/tag/netty-4.1.136.Final"},{"name":"https://github.com/netty/netty/releases/tag/netty-4.2.16.Final","tags":["x_refsource_MISC"],"url":"https://github.com/netty/netty/releases/tag/netty-4.2.16.Final"}],"affected":[{"vendor":"netty","product":"netty","versions":[{"version":">= 4.2.0.Final, < 4.2.16.Final","status":"affected"},{"version":"< 4.1.136.Final","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-07-29T17:58:35.543Z"},"descriptions":[{"lang":"en","value":"Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.136.Final and 4.2.16.Final, 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. This issue has been fixed in versions 4.1.136.Final and 4.2.16.Final."}],"source":{"advisory":"GHSA-c69g-56f8-xwqj","discovery":"UNKNOWN"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-29T18:07:07.017564Z","id":"CVE-2026-59900","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-07-29T18:07:24.906Z"}}]}}