CVE-2026-42581

5.8 MEDIUM

Netty is an asynchronous, event-driven network application framework

Published: 2026-05-13 · Last updated: 2026-05-18

Severity and scoring

CVSS: 5.8 MEDIUM
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
CWE: CWE-444

Affected products

Vendor	Product
netty	netty

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.

Source: NVD

References

[NVD]https://nvd.nist.gov/vuln/detail/CVE-2026-42581
[Vendor advisory]https://github.com/netty/netty/security/advisories/GHSA-xxqh-mfjm-7mv9
[Vendor advisory]https://github.com/netty/netty/security/advisories/GHSA-xxqh-mfjm-7mv9

Related CVEs

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CVE-2026-50560 — Netty is a network application framework for development of protocol servers and clients (5.3 MEDIUM)
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CVE-2026-50011 — Netty is a network application framework for development of protocol servers and clients (7.5 HIGH)
CVE-2026-50010 — Netty is a network application framework for development of protocol servers and clients (7.5 HIGH)
CVE-2026-50009 — Netty is a network application framework for development of protocol servers and clients (4.8 MEDIUM)

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