CVE Watch8 oct 2026

CVE-2021-21409

Netty is an open-source, asynchronous event-driven network application framework for rapid development of maintainable high performance prot

CVSS

5.9

Medio

EPSS

4.9%

p92

KEV

—

Exploit Today

0-100

Publicado: 30 mar 2021 · Última mod.: 8 oct 2026 · CWE-444

EPSS · 30d

4.9%EPSS · 30 días4.9%

2026-10-172026-11-13

Descripción técnica

Netty is an open-source, asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers & clients. In Netty (io.netty:netty-codec-http2) before version 4.1.61.Final there is a vulnerability that enables request smuggling. The content-length header is not correctly validated if the request only uses a single Http2HeaderFrame with the endStream set to to true. This could lead to request smuggling if the request is proxied to a remote peer and translated to HTTP/1.1. This is a followup of GHSA-wm47-8v5p-wjpj/CVE-2021-21295 which did miss to fix this one case. This was fixed as part of 4.1.61.Final.

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