Netty SPDY SETTINGS frame count materializes unbounded settings map

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-55831
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-21 00:17:35 UTC
Updated2026-07-22 19:37:49 UTC
DescriptionNetty 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.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS: 0.006300000 probability, percentile 0.464270000 (date 2026-07-22)

Problem Types: CWE-400 | CWE-770 | CWE-770 CWE-770: Allocation of Resources Without Limits or Throttling | CWE-400 CWE-400: Uncontrolled Resource Consumption

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1CNADECLARED7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Netty Netty All All All All
Application Netty Netty All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Netty Netty affected >= 4.2.0.Final, < 4.2.16.Final Not specified
CNA Netty Netty affected >= 4.1.0.Final, < 4.1.136.Final Not specified

References

ReferenceSourceLinkTags
github.com/netty/netty/releases/tag/netty-4.1.136.Final [email protected] github.com Release Notes
github.com/netty/netty/security/advisories/GHSA-6jqx-86gh-f27w [email protected] github.com Exploit, Vendor Advisory
github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b [email protected] github.com Patch
github.com/netty/netty/releases/tag/netty-4.2.16.Final [email protected] github.com Release Notes
github.com/netty/netty/commit/bb2ff68a1fb71cb4b0eb9a9e17b66c52aff680c6 [email protected] github.com Patch
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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