Bug 2488388 (CVE-2026-46340)

Summary:	CVE-2026-46340 netty-transport-sctp: Netty-transport-sctp: Denial of Service due to unbounded memory growth from SctpMessage fragments
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	anujha, aschwart, asoldano, aszczucz, bbaranow, bbrownin, bmaxwell, boliveir, bstansbe, dlofthou, drichtar, fmariani, gmalinko, istudens, ivassile, iweiss, janstey, jwon, mcarlett, mosmerov, mposolda, msvehla, nwallace, pdelbell, pesilva, pjindal, pmackay, rmartinc, rstancel, rstepani, ssilvert, sthorger, tcunning, thjenkin, vdosoudi, vmuzikar, yfang
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
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Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in netty-transport-sctp. A remote attacker can exploit this vulnerability by sending specially crafted, non-complete Stream Control Transmission Protocol (SCTP) message fragments. This can lead to unbounded memory growth within the application, causing a Denial of Service (DoS) condition. The affected component fails to limit the size or number of these fragments, allowing an attacker to consume excessive system resources.	Story Points:	---
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Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-06-12 15:01:57 UTC

Netty is a network application framework for development of protocol servers and clients. In versions of netty-transport-sctp prior to 4.1.135.Final and 4.2.15.Final, for each non-complete SctpMessage fragment the handler does `fragments.put(streamId, Unpooled.wrappedBuffer(frag, byteBuf))`, wrapping the previous accumulator and the new slice into a *new* CompositeByteBuf every time. After N fragments the accumulator is an N-deep chain of composites, each holding references and component arrays; readableBytes()/getBytes() on the final buffer recurse N levels. There is no limit on N, on total bytes, or on the number of streamIdentifiers an attacker can open (each gets its own map entry). A peer that never sets the `complete` flag can grow this structure indefinitely from tiny 1-byte DATA chunks. Versions 4.1.135.Final and 4.2.15.Final patch the issue.