GHSA-676x-f7gg-47vc

ghsaUSosv

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

view advisory published 2026-06-08Licence: CC-BY-4.0

### 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.

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describes (1)

Related CVEs.

IDseverity exploitable
CVE-2026-45674UScritical10.0OT highExploit
Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, Netty's DnsResolveContext fails to valid…
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