CVE-2026-55851
Review this vulnerability's source-backed evidence, with unavailable values and read failures kept distinct.
A permanent, source-backed tracker page. Values are shown only when returned; explicit gaps and read failures remain different states.
Detection and validation
Mapped metadata availability only. These signals do not change priority.
Sigma
Not mapped by tracked sources.
Atomic
Not mapped by tracked sources.
Nuclei
Not mapped by tracked sources.
What it is
ReportedNetty 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…
Source reported · Source: NVD · Source last published: · Source description excerpt; complete tracked detail loads below. · Source last updated: · Tracker data as of:
What is affected
ReportedNetty; codec-haproxy. Product-level identification only; no affected-version conclusion is available from this field.
Source reported · Source: NVD · Source last published: · Source last updated: · Tracker data as of:
Urgency and basis
ReportedTrack · 121.8
Tracker computed · Tracker decision tier from the evidence detailed below · Source last updated: · Tracker data as of:
Exploitation evidence
Not reportedNot reported by tracked sources.
What to do
ReportedA source remediation link is available. Validate that guidance against the affected product and your environment.
Source remediation ↗Source reported · Tracked source remediation field · Source last updated: · Tracker data as of:
Evidence detail
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