CVE-2026-44249

HIGH 8.1

Netty has an IPv6 Subnet Filter Bypass via Incorrect Comparator Masking

CVSS Score

8.1

EPSS Score

0.6%

EPSS Percentile

44th

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.

CWE	CWE-284 CWE-697
Vendor	netty
Product	netty
Published	Jun 11, 2026
Last Updated	Jul 23, 2026

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CVSS v3 Breakdown

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

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Affected Versions

netty / netty

>= 4.2.0.Final, < 4.2.15.Final < 4.1.135.Final

References

NVD ↗ CVE.org ↗ EPSS Data ↗