Bug 2505698 (CVE-2026-55851)

Summary:	CVE-2026-55851 io.netty/netty-codec-haproxy: Netty codec-haproxy: Denial of Service via crafted PROXY protocol v2 message
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	aazores, abrianik, anthomas, ant, anujha, aschwart, asoldano, aszczucz, ataylor, avibelli, bbaranow, bgeorges, bmaxwell, boliveir, bstansbe, ccranfor, cescoffi, chfoley, cmah, dandread, dbruscin, dhanak, dkreling, dlofthou, drichtar, drosa, dsimansk, eaguilar, ebaron, ehelms, ehugonne, ewittman, fmariani, fmongiar, ggainey, ggrzybek, gmalinko, gsmet, gtanzill, istudens, ivassile, iweiss, janstey, jbuscemi, jmartisk, jmatsuok, jnethert, jpasqual, jpechane, jraez, jtolenti, juwatts, jwon, kaycoth, kingland, kvanderr, lthon, manderse, mcarlett, mdellweg, mhulan, mnovotny, mosmerov, mposolda, msvehla, nipatil, nmoumoul, nwallace, olubyans, osousa, pantinor, parichar, pberan, pcreech, pesilva, pgallagh, pjindal, pmackay, probinso, rchan, rgodfrey, rguimara, rkubis, rmartinc, rruss, rstancel, rstepani, rsvoboda, sausingh, sbiarozk, sdawley, smallamp, ssilvert, sthorger, swoodman, tasato, tcunning, thjenkin, tmalecek, tqvarnst, vdosoudi, vmuzikar, yfang
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in Netty's codec-haproxy module. A remote attacker could exploit a vulnerability in the HAProxyMessageDecoder by sending a specially crafted PROXY protocol v2 message. This leads to unbounded buffer accumulation, causing a denial of service (DoS) due to memory exhaustion.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-07-21 22:43:23 UTC

Netty is a network application framework for development of protocol servers and clients. In versions 4.2.0.Final up to (but not including) 4.2.16.Final, and 4.1.0.Final up to (but not including) 4.1.135, the `HAProxyMessageDecoder` in Netty's `codec-haproxy` module performs protocol version detection by reading the 13th byte as a signed Java `byte` and widening it to `int` without masking; a PROXY protocol v2 binary prefix followed by version byte `0xFF` sign-extends to `-1`, collides with the decoder's need-more-data sentinel, and causes `ByteToMessageDecoder` to accumulate inbound bytes in an unbounded `cumulation` buffer until direct memory is exhausted. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.

Comment 1 errata-xmlrpc 2026-07-30 07:45:29 UTC

This issue has been addressed in the following products:

  Red Hat Build of Apache Camel 4.18 for Quarkus 3.33

Via RHSA-2026:48118 https://access.redhat.com/errata/RHSA-2026:48118