Vulnerability in io.netty:netty-codec-haproxy (CVE-2026-59919)
Summary
Vulnerability in io.netty:netty-codec-haproxy (CVE-2026-59919). Data can be tampered with by attackers. Exploitable via sourceAddress. Mitigation: upgrade to 4.1.136.Final or later.
Original description
The description as published by the source.
Netty is an asynchronous, event-driven network application framework. In versions prior to 4.1.136.Final and 4.2.16.Final, Netty's HAProxy encoder ( HAProxyMessageEncoder ) writes AF_UNIX source and destination socket addresses into the HAProxy V1 text protocol without validating them for CRLF characters, so an attacker who controls an AF_UNIX address can inject \r\n sequences and split the single PROXY header into multiple lines. This is possible because the V1 protocol uses CRLF as its line terminator and, unlike IPv4/IPv6 addresses whose format checks implicitly reject CRLF, AF_UNIX addresses are only validated for length (up to 108 bytes), allowing a forged second PROXY header line that spoofs the client source/destination IP to a downstream server or load balancer. The issue is fixed in versions 4.1.136.Final and 4.2.16.Final.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-59919 has been found in io.netty:netty-codec-haproxy.
Attackers can target a specific entry point like sourceAddress over the network to misuse the product.
Data can be tampered with by attackers. CVSS score: 5.5/10.
What to do: upgrade io.netty:netty-codec-haproxy to 4.1.136.Final or later.
If unsure, ask your IT team or search "io.netty:netty-codec-haproxy CVE-2026-59919" on the vendor's site.
CVE-2026-59919 (io.netty:netty-codec-haproxy) — CWE-93 / CVSS v3 5.5
Attack vector: local / no user interaction
Attack surface: sourceAddress / destinationAddress / HAProxyMessageEncoder / UNIX_STREAM
Patched: 4.1.136.Final — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-93) exists in io.netty:netty-codec-haproxy. Attackers reach the vulnerable code path via sourceAddress.
Check the vendor advisory for the affected versions of io.netty:netty-codec-haproxy. Attack surface: sourceAddress / destinationAddress / HAProxyMessageEncoder / UNIX_STREAM.
Severity: Medium (CVSS 5.5/10). Data can be tampered with by attackers.
Update to 4.1.136.Final.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで io.netty:netty-codec-haproxy を使っているサービスとバージョンを洗い出す。
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2Apply patch patch
Upgrade io.netty:netty-codec-haproxy to 4.1.136.Finalステージング環境で 4.1.136.Final に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
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3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-59919 netty
- Ubuntu UBUNTU-CVE-2026-59919 netty
References
- advisory github.com
- advisory github.com
- advisory nvd.nist.gov
- web github.com
- web github.com
- web github.com