VULNERABILITY INTELLIGENCE

CVE-2026-42581

CVSS score5.8 MEDIUM
EPSS probability0.63%
CISA KEVNot currently listed
Published2026-05-13
Last modified2026-09-18
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

Description

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.

Weakness classification

  • security-advisories@github.com: CWE-444
  • 0b0ca135-0b70-47e7-9f44-1890c2a1c46c: CWE-444

Primary references