Vulnerability in io.netty:netty-codec-http (CVE-2026-50020)
Summary
Vulnerability in io.netty:netty-codec-http (CVE-2026-50020). Risk of unauthorized operations or information disclosure. Exploitable via HttpObjectDecoder. Mitigation: upgrade to 4.1.135.Final or later.
Original description
The description as published by the source.
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, before reading the first request-line, HttpObjectDecoder skips every byte for which Character.isISOControl(b) is true (0x00–0x1F and 0x7F) as well as all whitespace. RFC 9112 §2.2 only asks servers to ignore empty CRLF lines preceding the request-line — a carefully scoped robustness allowance intended to handle HTTP/1.0 POST workarounds. Silently absorbing NUL bytes, SOH, STX, and other non-CRLF control characters goes significantly beyond this, and can be exploited for request-boundary confusion in pipelined or multiplexed transports where a front-end component treats those bytes differently. Versions 4.1.135.Final and 4.2.15.Final patch the issue.
Source: NIST National Vulnerability Database 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-2026-50020 has been found in io.netty:netty-codec-http.
Attackers can target a specific entry point like HttpObjectDecoder over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 5.3/10.
What to do: upgrade io.netty:netty-codec-http to 4.1.135.Final or later.
If unsure, ask your IT team or search "io.netty:netty-codec-http CVE-2026-50020" on the vendor's site.
CVE-2026-50020 (io.netty:netty-codec-http) — CWE-444 / CVSS v3 5.3
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: HttpObjectDecoder / true / ISO_CONTROL_OR_WHITESPACE / SKIP_CONTROL_CHARS_BYTES
Patched: 4.1.135.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-444) exists in io.netty:netty-codec-http. Attackers reach the vulnerable code path via HttpObjectDecoder without authentication.
Check the vendor advisory for the affected versions of io.netty:netty-codec-http. Attack surface: HttpObjectDecoder / true / ISO_CONTROL_OR_WHITESPACE / SKIP_CONTROL_CHARS_BYTES.
Severity: Medium (CVSS 5.3/10). Risk of unauthorized operations or information disclosure.
Update to 4.1.135.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-http 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-http to 4.1.135.Finalステージング環境で 4.1.135.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-2026-50020 netty
- Ubuntu UBUNTU-CVE-2026-50020 netty
References
- advisory github.com
- advisory nvd.nist.gov
- advisory github.com
- package github.com
- web github.com
- web github.com
- web github.com