CVE-2026-45416Network attack vector

Unauthenticated service interruption via eager ClientHello allocation

Published Jun 12, 2026 · Updated Jun 12, 2026

Resource exhaustion in Netty before 4.1.135.Final and 4.2.0.Final through 4.2.14.Final allows remote attackers to interrupt services. SslClientHelloHandler.decode() trusts a 24-bit ClientHello length and eagerly allocates that many bytes when default SNI constructors disable the length guard and timeout. An unauthenticated TLS connection can retain an allocation approaching 16 MiB until closure, so concurrent connections can exhaust memory and interrupt the hosting application.

CVSS severity7.5
High
EPSS probability0.86%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in Netty before 4.1.135.Final and 4.2.0.Final through 4.2.14.Final allows remote attackers to interrupt services. SslClientHelloHandler.decode() trusts a 24-bit ClientHello length and eagerly allocates that many bytes when default SNI constructors disable the length guard and timeout. An unauthenticated TLS connection can retain an allocation approaching 16 MiB until closure, so concurrent connections can exhaust memory and interrupt the hosting application.

The record

CVE
CVE-2026-45416
Published
Jun 12, 2026
Updated
Jun 12, 2026
Vendor
The Netty Project
Product
Netty
Classifications
CWE-770, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 12, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 12, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 4.1.135.Final
  2. Affected versionversion=>= 4.2.0.Final, < 4.2.15.Final

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Netty Project · Nettyversion=< 4.1.135.Final; version=>= 4.2.0.Final, < 4.2.15.Final

Published CVSS scores

7.5GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499.004Application or System Exploitation Flood

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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