CVE-2026-42579 PUBLISHED

Netty: DNS Codec Input Validation Bypass in Netty (Encoder + Decoder)

Assigner: GitHub_M
Reserved: 28.04.2026 Published: 13.05.2026 Updated: 13.05.2026

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Netty's DNS codec does not enforce RFC 1035 domain name constraints during either encoding or decoding. This creates a bidirectional attack surface: malicious DNS responses can exploit the decoder, and user-influenced hostnames can exploit the encoder. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

Metrics

CVSS 3.1

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

Attack Vector	Network	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	None
Privileges Required	None	Integrity Impact	High
User Interaction	None	Availability Impact	None

CVSS 3.1

Product Status

Vendor	netty
Product	netty
Versions	Version >= 4.2.0.Alpha1, < 4.2.13.Final is affected Version < 4.1.133.Final is affected

References

https://github.com/netty/netty/security/advisories/GHSA-cm33-6792-r9fm

Problem Types

CWE-20: Improper Input Validation CWE
CWE-400: Uncontrolled Resource Consumption CWE
CWE-626: Null Byte Interaction Error (Poison Null Byte) CWE