Vulnerability in io.netty:netty-codec-http2 (CVE-2026-59900)
Summary
Vulnerability in io.netty:netty-codec-http2 (CVE-2026-59900). Risk of unauthorized operations or information disclosure. Exploitable via Http2StreamFrameToHttpObjectCodec. 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. Prior to versions 4.1.136.Final and 4.2.16.Final, Netty's HTTP/2-to-HTTP/1.x translation layer (Http2StreamFrameToHttpObjectCodec and InboundHttp2ToHttpAdapter) fails to deduplicate or validate Host headers when an HTTP/2 client supplies both the :authority pseudo-header and a literal host header in a single HEADERS frame. The translator maps :authority to Host and separately copies the literal host header, producing an HttpRequest object containing two Host headers with attacker-controlled differing values. This issue has been 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-2026-59900 has been found in io.netty:netty-codec-http2.
Attackers can target a specific entry point like Http2StreamFrameToHttpObjectCodec 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-http2 to 4.1.136.Final or later.
If unsure, ask your IT team or search "io.netty:netty-codec-http2 CVE-2026-59900" on the vendor's site.
CVE-2026-59900 (io.netty:netty-codec-http2) — CWE-444 / CVSS v3 5.3
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: Http2StreamFrameToHttpObjectCodec / InboundHttp2ToHttpAdapter / Host / host
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-444) exists in io.netty:netty-codec-http2. Attackers reach the vulnerable code path via Http2StreamFrameToHttpObjectCodec without authentication.
Check the vendor advisory for the affected versions of io.netty:netty-codec-http2. Attack surface: Http2StreamFrameToHttpObjectCodec / InboundHttp2ToHttpAdapter / Host / host.
Severity: Medium (CVSS 5.3/10). Risk of unauthorized operations or information disclosure.
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-http2 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-http2 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-2026-59900 netty
- Ubuntu UBUNTU-CVE-2026-59900 netty
References
- advisory github.com
- advisory github.com
- advisory nvd.nist.gov
- web github.com
- web github.com
- web github.com