CVE-2026-45674

Updated on 08 Jun 2026

Severity

8.7 High severity

Details

CVSS score
8.7
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N

Overview

About vulnerability

Summary

Netty’s DnsResolveContext fails to validate the origin (bailiwick) of CNAME records in DNS responses.

Details

In io.netty.resolver.dns.DnsResolveContext#buildAliasMap, the resolver processes the ANSWER section of a DNS response and blindly caches all CNAME records it finds.

According to https://datatracker.ietf.org/doc/html/rfc5452#section-6

Care must be taken to only accept
data if it is known that the originator is authoritative for the
QNAME or a parent of the QNAME.
One very simple way to achieve this is to only accept data if it is
part of the domain for which the query was intended.

Impact

DNS Cache Poisoning (Bailiwick Bypass). Any application using Netty’s DNS resolver is impacted.

Details

Fixes