CVE-2026-55831

HIGH

Netty SPDY SETTINGS frame count materializes unbounded settings map

Title source: cna
STIX 2.1

Description

Netty is a network application framework for development of protocol servers and clients. Prior to 4.1.136.Final and 4.2.16.Final, Netty's SPDY SETTINGS decoder accepts a peer-declared SETTINGS entry count up to the 24-bit frame-length limit and materializes every unique setting ID in `DefaultSpdySettingsFrame`, allowing a remote SPDY/3.1 peer to send a syntactically valid roughly 2 MiB SETTINGS frame that creates 262144 map entries and amplifies network input into heap growth and ordered-map insertion work. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.

References (5)

Core 5

Scores

CVSS v3 7.5
EPSS 0.0042
EPSS Percentile 34.9%
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 poc
Automatable yes
Technical Impact partial

Details

CWE
CWE-400 CWE-770
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 21, 2026