CVE-2026-44249

Netty has an IPv6 Subnet Filter Bypass via Incorrect Comparator Masking

HIGH
8.1
CVSS Score
Published: June 11, 2026 at 08:46 PM UTC
Updated: September 18, 2026 at 02:29 PM UTC
12 products affected across 2 vendorsNettyBuild of KeycloakOpenShift AI

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Severity
HIGH8.1
Exploit prediction
EPSS 1.0%
SSVC
No known exploit

Description

Netty is a network application framework for development of protocol servers and clients. In netty-handler prior to versions 4.1.135.Final and 4.2.15.Final, an attacker can bypass IPv6 subnet rules due to an incorrect masking operation in IpSubnetFilterRule.compareTo(). Valid public IP addresses can bypass the restrictions. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 4.1.135v < 4.1.135.Finalv < 4.2.15.Final4.2.0 ≤ v < 4.2.15
Affected range stops below 4.1.135, so it looks safe — our inference, not a vendor statement
Affected range stops below 4.1.135.Final, so it looks safe — our inference, not a vendor statement
Affected range stops below 4.2.15, so it looks safe — our inference, not a vendor statement
Affected range stops below 4.2.15.Final, so it looks safe — our inference, not a vendor statement
All versions
All versions

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (27)

x_refsource_CONFIRMVendor Advisory
Source: cverecord
https://github.com/netty/netty/security/advisories/GHSA-3qp7-7mw8-wx86
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/netty/netty/releases/tag/netty-4.1.135.Final
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/netty/netty/releases/tag/netty-4.2.15.Final
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://access.redhat.com/errata/RHSA-2026:26017
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://access.redhat.com/errata/RHSA-2026:26018
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://access.redhat.com/errata/RHSA-2026:26586
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://access.redhat.com/errata/RHSA-2026:28573
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://access.redhat.com/security/cve/CVE-2026-44249

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.1HIGHGitHub_M
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-284CWE-697CWE-1287

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