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Vulnerability · Published Jun 12, 2026 · Assigned by GitHub_M

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

High 7.5

In plain English

A high-severity security flaw in netty from netty. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 50% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.6%top 50.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

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 packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12nettyno fix listedDEBIAN-CVE-2026-44893
Debian:13nettyno fix listedDEBIAN-CVE-2026-44893
Debian:14nettyno fix listedDEBIAN-CVE-2026-44893
Mavenio.netty:netty-codec-haproxy4.1.135.FinalGHSA-cc37-9q2j-3hfv
Mavenio.netty:netty-codec-haproxy4.2.15.FinalGHSA-cc37-9q2j-3hfv
Ubuntu:25.10nettyno fix listedUBUNTU-CVE-2026-44893
Ubuntu:26.10nettyno fix listedUBUNTU-CVE-2026-44893

Affected products (as reported)

VendorProductVersions
netty netty >= 4.2.0.Final, < 4.2.15.Final< 4.1.135.Final

Weakness: CWE-703, CWE-805 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References