Netty has an IPv6 Subnet Filter Bypass via Incorrect Comparator Masking
Summary
An attacker can bypass IPv6 subnet rules due to an incorrect masking operation in IpSubnetFilterRule.compareTo(). Valid public IP addresses can bypass the restrictions.
Details
io.netty.handler.ipfilter.IpSubnetFilterRule#compareTo(java.net.InetSocketAddress) method performs a bitwise AND between the incoming IP address and the configured networkAddress, instead of the subnetMask.
Impact
Access Control Bypass. Attacker can bypass IpSubnetFilter IPv6 access controls.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Java / Kotlin (Maven) | io.netty:netty-handler | >= 4.2.0.Final, < 4.2.15.Final, < 4.1.135.Final | 4.2.15.Final, 4.1.135.Final |
References
- CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H- Weakness (CWE)
CWE-284, CWE-697- Platform
- Java / Kotlin (Maven)
- Package
io.netty:netty-handler- Disclosed
- 08.06.2026
- Updated
- 11.10.2026 13:20
Sources and licenses
OSV / GitHub Advisory Database - GHSA-3qp7-7mw8-wx86 - CC BY 4.0
Vulnerability history: io.netty:netty-handler
All published vulnerabilities of this package (Java / Kotlin (Maven)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 12
- First → latest
- 02.2020 09.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 1
- High 7
- Medium 4
Disclosures per year
- 2020: 4
- 2021: 0
- 2022: 1
- 2023: 1
- 2024: 0
- 2025: 1
- 2026: 5
-
Netty has an IPv6 Subnet Filter Bypass via Incorrect Comparator Masking this entry
Know which vulnerabilities affect your application
With the DockRay integration and software inventory enabled, DockRay checks reported component versions against known vulnerabilities and notifies you about confirmed matches. Coverage depends on the supported technology and available advisory data.