PT-2026-38280 · Netty · Netty

Published

2026-05-06

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Updated

2026-05-18

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CVE-2026-42577

CVSS v3.1

7.5

High

VectorAV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Name of the Vulnerable Software and Affected Versions Netty versions 4.2.0.Final through 4.2.12.Final
Description Netty's epoll transport fails to detect and close TCP connections that receive a RST after being half-closed. This occurs when a connection has ALLOW HALF CLOSURE enabled or is in a half-closed state via the HTTP codec, and the remote peer sends a FIN followed by a RST. Because epollOutReady() is a no-op without a pending flush and epollInReady() short-circuits when input is marked as shutdown, the EPOLLERR/EPOLLHUP error condition is not processed, and channelInactive is never triggered. This leads to stale channels that exhaust file descriptors, memory, or connection-count limits. In certain code paths where clearEpollIn0() is not called during the ChannelInputShutdownReadComplete event, it can cause a 100% CPU busy-loop in the event loop thread, starving other multiplexed connections.
Recommendations Update to version 4.2.13.Final. Configure idle timeouts on connections to limit the lifetime of stale channels.

Fix

Missing Release of Resource after Effective Lifetime

Weakness Enumeration

Related Identifiers

CLEANSTART-2026-AO61361
CLEANSTART-2026-GX01236
CLEANSTART-2026-JW30455
CLEANSTART-2026-KV09488
CLEANSTART-2026-LE11246
CLEANSTART-2026-PO27799
CLEANSTART-2026-RD06185
CLEANSTART-2026-VJ37814
CLEANSTART-2026-WG59699
CVE-2026-42577
GHSA-RWM7-X88C-3G2P

Affected Products

Netty