Bug 2488399 (CVE-2026-47244)

Summary:	CVE-2026-47244 netty-codec-http2: Netty: Denial of Service via uncontrolled HTTP/2 concurrent streams
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	aazores, abrianik, ant, anujha, aschwart, asoldano, aszczucz, ataylor, avibelli, bbaranow, bbrownin, bgeorges, bmaxwell, boliveir, bstansbe, ccranfor, cescoffi, chfoley, cmah, dandread, dbruscin, dhanak, dkreling, dlofthou, drichtar, drosa, dsimansk, eaguilar, ebaron, ehugonne, ewittman, fmariani, fmongiar, ggrzybek, gmalinko, gsmet, istudens, ivassile, iweiss, janstey, jkoehler, jmartisk, jnethert, jolong, jpechane, jraez, jwon, kaycoth, kgaikwad, kingland, kvanderr, lphiri, lthon, manderse, mcarlett, mnovotny, mosmerov, mposolda, mstipich, msvehla, nipatil, nwallace, olubyans, pantinor, parichar, pberan, pesilva, pgallagh, pjindal, pmackay, probinso, rexwhite, rgodfrey, rguimara, rkubis, rmartinc, rruss, rstancel, rstepani, rsvoboda, sausingh, sbiarozk, sdawley, ssilvert, sthirugn, sthorger, swoodman, tasato, tcunning, thjenkin, tqvarnst, vdosoudi, vmuzikar, yfang
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
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Doc Text:	A flaw was found in Netty, a network application framework. A remote attacker can exploit this vulnerability by sending a large number of HTTP/2 stream requests to a Netty HTTP/2 server. If the server does not explicitly limit concurrent streams, it can lead to the allocation of numerous long-lived stream objects. This excessive resource consumption can result in a denial of service (DoS), making the server unavailable to legitimate users.	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 15:02:34 UTC

Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, DefaultHttp2Connection.DefaultEndpoint initialises maxActiveStreams/maxStreams to Integer.MAX_VALUE, and Http2Settings never inserts SETTINGS_MAX_CONCURRENT_STREAMS by default (Http2Settings.java:305-307 only clamps a user-supplied value). Unless the application explicitly calls initialSettings().maxConcurrentStreams(n), a Netty HTTP/2 server advertises no limit and enforces none locally. Each open stream allocates a DefaultStream object, PropertyMap slots, flow-controller state and IntObjectHashMap entry; with ~2^30 permissible odd stream IDs a single TCP connection can create hundreds of thousands of long-lived stream objects. This is also the precondition for CVE-2023-44487-style Rapid-Reset amplification, where the absence of a low concurrent cap multiplies backend work. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

Comment 3 errata-xmlrpc 2026-08-04 14:00:39 UTC

This issue has been addressed in the following products:

  Red Hat JBoss Enterprise Application Platform 8.1

Via RHSA-2026:50085 https://access.redhat.com/errata/RHSA-2026:50085