{"id":"CVE-2026-42581","aliases":["GHSA-xxqh-mfjm-7mv9"],"url":"https://o3.security/vulnerability/CVE-2026-42581","summary":"Netty: HTTP/1.0 TE+CL Coexistence Bypasses Smuggling Sanitization","details":"Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, HttpObjectDecoder strips a conflicting Content-Length header when a request carries both Transfer-Encoding: chunked and Content-Length, but only for HTTP/1.1 messages. The guard is absent for HTTP/1.0. An attacker that sends an HTTP/1.0 request with both headers causes Netty to decode the body as chunked while leaving Content-Length intact in the forwarded HttpMessage. Any downstream proxy or handler that trusts Content-Length over Transfer-Encoding will disagree on message boundaries, enabling request smuggling. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.","published":"2026-05-13T17:54:44.492Z","modified":"2026-08-08T03:30:20.196917420Z","cvss":{"score":5.8,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Maven","name":"io.netty:netty-codec-http","fixedVersion":"4.2.13.Final"},{"ecosystem":"Maven","name":"io.netty:netty-codec-http","fixedVersion":"4.1.133.Final"}],"fix":null,"references":[{"type":"WEB","url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42581.json"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:23808"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:24502"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:25123"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:28010"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:36820"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:37390"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:42644"},{"type":"ADVISORY","url":"https://access.redhat.com/security/cve/CVE-2026-42581"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42581.json"},{"type":"ADVISORY","url":"https://github.com/netty/netty/security/advisories/GHSA-xxqh-mfjm-7mv9"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-42581"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2477232"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-08T03:30:20.196917420Z"}}