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High severity8.7NVD Advisory· Published Jun 8, 2026· Updated Jun 8, 2026

Netty Vulnerable to DNS Cache Poisoning via Missing Bailiwick Checks in CNAME Records

CVE-2026-45674

Description

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.

Affected products

1

Patches

0

No patches discovered yet.

Vulnerability mechanics

No source-code context for this CVE — mechanics is only generated when we can read the actual fix diff. Without that, the four sections (root cause, attack vector, affected code, fix) would be speculation rather than analysis.

References

4

News mentions

1