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© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2026-45416

35
FAUCET Score

Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, SslClientHelloHandler.decode() reads the 24-bit TLS handshake length and, when the ClientHello does not fit in the first record, eagerly allocates `ctx.alloc().buffer(handshakeLength)` (line 161). The guard at line 140 is `handshakeLength > maxClientHelloLength && maxClientHelloLength != 0`, and the commonly-used SniHandler/AbstractSniHandler constructors (SniHandler(Mapping), SniHandler(AsyncMapping), AbstractSniHandler()) pass maxClientHelloLength=0 and handshakeTimeoutMillis=0, so the length guard is disabled and no timeout is scheduled. A 16 MiB request exceeds the default pooled chunk size and becomes a huge/unpooled allocation performed immediately. The buffer is retained in the handler until the channel closes. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

First published: Jun 12, 2026Last modified: Jun 12, 2026

Impacted Technologies

VendorProductVersion(s)CPE
< 4.1.135CPE matchmatch criteria
cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*
>= 4.2.0, < 4.2.15CPE matchmatch criteria
cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.48%
Probability of exploitation in next 30 days
EPSS Percentile
38.6%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0048 is in the 17th percentile among its peer group of 51,551 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (3)

mavenpatch availablevia ghsa
Product: io.netty:netty-handlerFixed in: 4.2.15.Final
mavenpatch availablevia ghsa
Product: io.netty:netty-handlerFixed in: 4.1.135.Final
github_advisoryvendor investigatingvia nvd_reference
View patch

Vendor Advisories (1)

mavenGHSA-x4gw-5cx5-pgmhhigh

Netty: SNI handler pre-allocates up to 16 MiB from nine attacker bytes

Jun 8, 2026

References

access.redhat.com / errata/RHSA-2026:26017
access.redhat.com / errata/RHSA-2026:26018
access.redhat.com / errata/RHSA-2026:26586
access.redhat.com / errata/RHSA-2026:28573
access.redhat.com / errata/RHSA-2026:34608
access.redhat.com / errata/RHSA-2026:37390
access.redhat.com / errata/RHSA-2026:41951
access.redhat.com / security/cve/CVE-2026-45416
bugzilla.redhat.com / show_bug.cgi
security.access.redhat.com / data/csaf/v2/vex/2026/cve-2026-45416.json
github.com / netty/netty/releases/tag/netty-4.1.135.Final
Release Notes
github.com / netty/netty/releases/tag/netty-4.2.15.Final
Release Notes
github.com / netty/netty/security/advisories/GHSA-x4gw-5cx5-pgmh
Vendor Advisory