Affected: CleanStart: hazelcast, CleanStart: keycloak, CleanStart: thingsboard

CVE-2026-48059 affects multiple packages. This issue is resolved in later releases. See references for individual vulnerability details.

Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, the HAProxy PROXY protocol v2 codec in netty leaks native or heap memory on every connection when a client sends a syntactically valid header containing nested `PP2_TYPE_SSL` TLVs (type-length-value records) at depth two or greater. The leak occurs on the successful parse path — no exception is thrown, the message fires downstream, the decoder removes itself, and the application releases the `HAProxyMessage` normally. Yet the underlying cumulation buffer (a pooled, potentially direct `ByteBuf` allocated by the channel) remains permanently pinned. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

Affected: Maven: io.netty:netty-codec-haproxy

### Impact The HAProxy PROXY protocol v2 codec in netty leaks native or heap memory on every connection when a client sends a syntactically valid header containing nested `PP2_TYPE_SSL` TLVs (type-length-value records) at depth two or greater. The leak occurs on the successful parse path — no exception is thrown, the message fires downstream, the decoder removes itself, and the application releases the `HAProxyMessage` normally. Yet the underlying cumulation buffer (a pooled, potentially direct `ByteBuf` allocated by the channel) remains permanently pinned.

netty-4.1.135-1.1 on GA media

eclipse-vertx/vert.x: eclipse-vertx/vert.x: Denial of Service via TLS handshake with wildcard server name netty-handler: netty-handler: IPv6 subnet rule bypass due to incorrect masking operation netty-codec-haproxy: Netty-codec-haproxy: Denial of Service via malformed HAProxy message netty-handler: Netty: Denial of Service due to eager buffer allocation in TLS handshake netty-resolver-dns: Netty DNS resolver: DNS Cache Poisoning via predictable transaction IDs netty-resolver-dns: Netty: Information disclosure and data manipulation due to improper CNAME record validation netty-codec-http2: Netty: Denial of Service via uncontrolled HTTP/2 concurrent streams io.netty/netty-resolver-dns: Netty has Insufficient Bailiwick Validation for NS Records netty-codec-http2: netty-codec-http2: Denial of Service due to resource leak netty-codec-haproxy: Netty HAProxy PROXY protocol v2 codec: Denial of Service via memory leak from crafted PROXY protocol headers netty-handler: Netty: Improper trust manager handling leads to hostname verification bypass netty-codec-http: Netty: Data manipulation via request-boundary confusion in HttpObjectDecoder io.quarkus/quarkus-vertx-http: Quarkus: Authorization bypass in HTTP path-based policies via encoded characters netty-codec-http2: Netty: Denial of Service due to HTTP/2 max header size handling

Affected: Ubuntu:Pro:14.04:LTS: netty, Ubuntu:Pro:16.04:LTS: netty, Ubuntu:Pro:18.04:LTS: netty, Ubuntu:Pro:20.04:LTS: netty, Ubuntu:Pro:22.04:LTS: netty, Ubuntu:Pro:24.04:LTS: netty, Ubuntu:25.10: netty, Ubuntu:Pro:26.04:LTS: netty

Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, the HAProxy PROXY protocol v2 codec in netty leaks native or heap memory on every connection when a client sends a syntactically valid header containing nested `PP2_TYPE_SSL` TLVs (type-length-value records) at depth two or greater. The leak occurs on the successful parse path — no exception is thrown, the message fires downstream, the decoder removes itself, and the application releases the `HAProxyMessage` normally. Yet the underlying cumulation buffer (a pooled, potentially direct `ByteBuf` allocated by the channel) remains permanently pinned. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Netty ausnutzen, um Sicherheitsvorkehrungen zu umgehen, Daten zu manipulieren, vertrauliche Informationen offenzulegen oder einen Denial-of-Service-Zustand herbeizuführen.