CVE-2026-42579

High

Description

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.

SeverityHigh

CVSS7.5

Exploit probability—

ProductNetty

PublishedMay 13, 2026

First seenMay 13, 2026

Weakness typeCWE-20Improper input validation CWE-400Uncontrolled resource consumption CWE-626CWE-626

How to fix

Update

netty netty4.1.133, 4.2.13 or later
io.netty:netty-codec-dns4.2.13.Final, 4.1.133.Final or later

Vendor advisories

Affected products

Product	Affected versions	Fixed in
netty netty	v < 4.1.133, 4.2.0 ≤ v < 4.2.13	4.1.133, 4.2.13
io.netty:netty-codec-dnsMaven	4.2.0.Alpha1 ≤ v < 4.2.13.Final, v < 4.1.133.Final	4.2.13.Final, 4.1.133.Final

Check your version

Choose the product and enter the version you run to see whether it falls in the affected range.

In the Intelligence 360 plan

Attack Surface Management

See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.