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Echo: io.netty:netty-handler: security update to 4.1.137.Final

high Tenable Cloud Security Plugin ID 455204

Description

There are packages installed that are affected by a vulnerability referenced in the following CVE:

 - Netty is an asynchronous, event-driven network application framework. Prior to 4.1.137.Final and
 4.2.17.Final, the default io.netty.handler.ssl.SniHandler constructors use the pre-handshake ClientHello
 aggregation path in handler/src/main/java/io/netty/handler/ssl/SslClientHelloHandler.java at
 io.netty.handler.ssl.SslClientHelloHandler#decode, where handshakeBuffer.clear() and writeBytes() recopy
 all previously received body bytes for every additional TLS record. An unauthenticated remote peer can
 advertise a large ClientHello and deliver its body in thousands of tiny records, causing quadratic CPU
 work on the event loop before the TLS handshake completes and degrading TLS handling for other clients.
 This issue is fixed in versions 4.1.137.Final and 4.2.17.Final. (CVE-2026-75596)

Solution

Update the io.netty:netty-handler library and its related packages to version 4.1.137.Final or later.

See Also

https://advisory.echohq.com/cve/CVE-2026-75596

Plugin Details

Severity: High

ID: 455204

Version: Revision 1.1

Type: Local

Published: 10/1/2026

Updated: 10/1/2026

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.63

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C

CVSS Score Source: CVE-2026-75596

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

CVSS v4

Risk Factor: High

Base Score: 8.7

Threat Score: 6.6

Threat Vector: CVSS:4.0/E:U

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Vulnerability Information

Exploit Ease: No known exploits are available

Patch Publication Date: 9/28/2026

Vulnerability Publication Date: 8/19/2026

Reference Information

CVE: CVE-2026-75596