CVE-2026-42579: Netty

Critical severity, CVSS 9.1. EPSS: 0.8% chance of exploitation in the next 30 days.

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.

Affected products

• Netty Netty: before 4.1.133 (fixed in 4.1.133); from 4.2.0, before 4.2.13 (fixed in 4.2.13)

Published 2026-05-13. Last modified 2026-09-18.