Bug 2488407 (CVE-2026-50560)

Summary: CVE-2026-50560 netty-codec-http2: Netty: Denial of Service due to HTTP/2 max header size handling
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: 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, pdelbell, 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   
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A flaw was found in Netty, a network application framework. A remote attacker can exploit a vulnerability in the HTTP/2 (Hypertext Transfer Protocol version 2) maximum header size handling. By sending a specific SETTINGS_MAX_HEADER_LIST_SIZE setting, an attacker can cause Netty to produce an exception when writing response headers. This issue is similar to an HTTP/2 Rapid Reset attack and can lead to a Denial of Service (DoS).
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Description OSIDB Bzimport 2026-06-12 16:01:22 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, Netty HTTP/2 max header size handling produces an attack similar to HTTP/2 Rapid Reset. There is a setting in the http2 specification called `SETTINGS_MAX_HEADER_LIST_SIZE`. When a client sends that setting to Netty, it appears that Netty will behave as follows: read the request; proxy the request to the origin; attempt to produce a response; and create an exception while writing the headers for the response. Functionally, this should be similar to the http2 reset attack, but with a different on-the-wire signature. Versions 4.1.135.Final and 4.2.15.Final patch the issue.
Comment 3 errata-xmlrpc 2026-08-04 14:00:34 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