Bug 2505698 (CVE-2026-55851) - CVE-2026-55851 io.netty/netty-codec-haproxy: Netty codec-haproxy: Denial of Service via crafted PROXY protocol v2 message
Summary: CVE-2026-55851 io.netty/netty-codec-haproxy: Netty codec-haproxy: Denial of S...
Keywords:
Status: NEW
Alias: CVE-2026-55851
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-07-21 22:43 UTC by OSIDB Bzimport
Modified: 2026-07-30 07:45 UTC (History)
103 users (show)

Fixed In Version:
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System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2026:48118 0 None None None 2026-07-30 07:45:34 UTC

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
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