Vulnerability in io.netty:netty-transport-native-epoll (CVE-2026-42577)
Summary
Vulnerability in io.netty:netty-transport-native-epoll (CVE-2026-42577). Risk of unauthorized operations or information disclosure. Exploitable via ALLOW_HALF_CLOSURE. Mitigation: upgrade to 4.2.13.Final or later.
Original description
The description as published by the source.
Netty is an asynchronous, event-driven network application framework. From 4.2.0.Final to 4.2.13.Final , Netty's epoll transport fails to detect and close TCP connections that receive a RST after being half-closed, leading to stale channels that are never cleaned up and, in some code paths, a 100% CPU busy-loop in the event loop thread. This vulnerability is fixed in 4.2.13.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-2026-42577 has been found in io.netty:netty-transport-native-epoll.
Attackers can target a specific entry point like ALLOW_HALF_CLOSURE over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: upgrade io.netty:netty-transport-native-epoll to 4.2.13.Final or later.
If unsure, ask your IT team or search "io.netty:netty-transport-native-epoll CVE-2026-42577" on the vendor's site.
CVE-2026-42577 (io.netty:netty-transport-native-epoll) — CWE-772 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: ALLOW_HALF_CLOSURE / EPOLLERR / EPOLLHUP / channelInactive
Patched: 4.2.13.Final — apply immediately
Workaround: configure idle timeouts on connections to limit the lifetime of stale channels.
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-772) exists in io.netty:netty-transport-native-epoll. Attackers reach the vulnerable code path via ALLOW_HALF_CLOSURE without authentication.
Check the vendor advisory for the affected versions of io.netty:netty-transport-native-epoll. Attack surface: ALLOW_HALF_CLOSURE / EPOLLERR / EPOLLHUP / channelInactive.
Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure.
Update to 4.2.13.Final.
Workaround: configure idle timeouts on connections to limit the lifetime of stale channels.
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
-
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-transport-native-epoll を使っているサービスとバージョンを洗い出す。
-
2Apply temporary workaround mitigate
configure idle timeouts on connections to limit the lifetime of stale channels.パッチが適用されるまでの応急処置として、configure idle timeouts on connections to limit the lifetime of stale channels. を実施。回避策の副作用 (機能低下) を確認した上で。
-
3Apply patch patch
Upgrade io.netty:netty-transport-native-epoll to 4.2.13.Finalステージング環境で 4.2.13.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。
-
4Post-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-2026-42577 netty
- Ubuntu UBUNTU-CVE-2026-42577 netty
References
- advisory github.com
- advisory nvd.nist.gov
- advisory github.com
- package github.com
- patch github.com
- patch github.com
- web github.com