CVE-2026-56745

HIGH

Netty SpdyHttpDecoder: ByteBuf Reference Leak on RST_STREAM Leads to Native Memory Exhaustion

Title source: cna
STIX 2.1

Description

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.

Scores

CVSS v3 7.5
EPSS 0.0050
EPSS Percentile 40.2%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact partial

Details

CWE
CWE-400
Status published
Products (5)
io.netty/netty-codec-http 4.1.0.Final - 4.1.136.FinalMaven
io.netty/netty-codec-http 4.2.0.Final - 4.2.16.FinalMaven
netty/netty 4.1.0 - 4.1.136
netty/netty >= 4.1.0.Final, < 4.1.136.Final
netty/netty >= 4.2.0.Final, < 4.2.16.Final
Published Jul 21, 2026
Tracked Since Jul 22, 2026