CVE-2026-45674
Published:June 09, 2026
Updated:June 09, 2026
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 Packages
https://github.com/netty/netty.git (GITHUB):
Affected version(s) >=netty-4.0.0.Alpha1 <netty-4.1.135.FinalFix Suggestion:
Update to version netty-4.1.135.Finalhttps://github.com/netty/netty.git (GITHUB):
Affected version(s) >=netty-4.2.0.Final <netty-4.2.15.FinalFix Suggestion:
Update to version netty-4.2.15.Finalio.netty:netty-resolver-dns (JAVA):
Affected version(s) >=4.1.0.Beta4 <4.1.135.FinalFix Suggestion:
Update to version 4.1.135.Finalio.netty:netty-resolver-dns (JAVA):
Affected version(s) >=4.2.0.Final <4.2.15.FinalFix Suggestion:
Update to version 4.2.15.FinalRelated Resources (4)
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Contact UsCVSS v4
Base Score:
9.4
Attack Vector
NETWORK
Attack Complexity
HIGH
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
HIGH
Vulnerable System Availability
NONE
Subsequent System Confidentiality
HIGH
Subsequent System Integrity
HIGH
Subsequent System Availability
NONE
CVSS v3
Base Score:
8.7
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
NONE
Weakness Type (CWE)
Insufficient Verification of Data Authenticity