Vulnerability in Netty (CVE-2026-62243)
Summary
Vulnerability in Netty (CVE-2026-62243). Confidential information can be exposed externally. Mitigation: upgrade to 4.2.17.Final or later.
Original description
The description as published by the source.
Netty (io.netty:netty-handler) versions from 4.2.0.Final through 4.2.16.Final and versions through 4.1.136.Final disable TLS hostname verification on the SslProvider.OPENSSL client path when a plain (non-extended) X509TrustManager is used and Unsafe-based trust-manager wrapping is unavailable (Java 25+). In this configuration the OpenSSL client does not perform hostname verification, allowing a man-in-the-middle attacker to present a certificate issued for a different hostname that is accepted without validation. Fixed in 4.2.17.Final and 4.1.137.Final.
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-2026-62243 has been found in Netty.
Confidential information can be exposed externally. CVSS score: 7.5/10.
What to do: upgrade Netty to 4.2.17.Final or later.
If unsure, ask your IT team or search "Netty CVE-2026-62243" on the vendor's site.
CVE-2026-62243 (Netty) — CWE-297 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: 4.2.17.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-297) exists in Netty.
Check the vendor advisory for the affected versions of Netty.
Severity: High (CVSS 7.5/10). Confidential information can be exposed externally.
Update to 4.2.17.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. Run grep -r 'Netty' . against your dependency files (package-lock.json, requirements.txt, go.sum) 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
grep -r 'Netty' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
Nettyを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade Netty to 4.2.17.Finalステージング環境で 4.2.17.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。
-
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。
References
- web disclosure@vulncheck.com
- web disclosure@vulncheck.com
- web nvd.nist.gov
- web github.com