23 Oct 2026 15:48:27 UTC
Netty: HTTP/1.0 TE+CL Coexistence Bypasses Smuggling Sanitization
cve-program · CVE-2026-42581 · Published
CVE-2026-42581
Netty: HTTP/1.0 TE+CL Coexistence Bypasses Smuggling Sanitization
CVSS 3.1 5.8 MEDIUMCheck source for fixed versionsKEV status unknown
cve-program · CVE-2026-42581
PublishedNetty 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.
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