CVE-2026-44893 — Netty: HAProxy SSL TLV parsing leaks retained slice on invalid TLV length

Description (CNA)

Netty is a network application framework for development of protocol servers and clients. In netty-codec-haproxy prior to versions 4.1.135.Final and 4.2.15.Final, when decoding a PP2_TYPE_SSL TLV, HAProxyMessage.readNextTLV() first calls `header.retainedSlice(header.readerIndex(), length)` and only then reads the 1-byte client field and 4-byte verify field. If the attacker sets the TLV length below 5, the subsequent readByte/readInt throws IndexOutOfBoundsException. HAProxyMessageDecoder only catches HAProxyProtocolException around this call, so the IOOBE propagates and the retained slice on the pooled cumulation buffer is never released. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

Affected (CNA)

Vendor / product	Versions
netty / netty	affected >= 4.2.0.Final, < 4.2.15.Final; affected < 4.1.135.Final

CWE

CWE-703

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.

redhat-SADP

A flaw was found in netty-codec-haproxy, a component of the Netty network application framework. A remote attacker can exploit this vulnerability by sending a specially crafted HAProxy message with a malformed PP2_TYPE_SSL TLV (Type-Length-Value) header. This can lead to an IndexOutOfBoundsException and prevent the release of retained memory, ultimately causing a Denial of Service (DoS) condition for the affected application.