High [CVE-2026-56745] Denial of Service via memory exhaustion in SPDY-to-HTTP codec

Netty is a network application framework for development of protocol servers and clients.

In versions 4.2.0.Final through 4.2.15.Final and 4.1.0.Final through 4.1.135.Final, the `SpdyHttpDecoder` handler in Netty's SPDY-to-HTTP codec allocates a pooled `ByteBuf` when processing a client-initiated `SYN_STREAM` frame with `FLAG_FIN=0` and stores the partially constructed `FullHttpRequest` in `messageMap`; when the remote peer sends `RST_STREAM` for that stream or the accumulated content exceeds `maxContentLength`, the decoder removes the entry but does not release the pooled `ByteBuf`, causing native memory exhaustion.

This issue is fixed in versions 4.1.136.Final and 4.2.16.Final. A flaw was found in Netty.

This oversight leads to native memory exhaustion, which can result in a Denial of Service (DoS) for the affected system. This is an Important denial of service vulnerability in Netty's SPDY-to-HTTP codec, affecting Red Hat products that utilize vulnerable versions of Netty.

Red Hat severity: Important — CVSS 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H). Weakness: CWE-772.

Affected products named by the advisory: Red Hat build of Apache Camel 4.18.3 for Spring Boot 3.5.16; Red Hat Build of Apache Camel 4.18 for Quarkus 3.33; Red Hat build of Quarkus 3.27.4.SP3; Red Hat build of Quarkus 3.33.2.SP3; and 19 more.