CVE-2026-45674 — Vulnerability in io.netty:netty-resolver-dns —...

HIGH

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

Published June 8, 2026Updated September 18, 2026Source: osv

Summary

### 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.

Advisory Timeline

First published June 8, 2026 (126 days ago).
Last revised September 18, 2026 — 102 days after initial publication.

Remediation

Upgrade to the fixed version using your package manager.

Maven

Update io.netty:netty-resolver-dns to 4.2.15.Final or later

<!-- Update pom.xml dependency version to 4.2.15.Final for io.netty:netty-resolver-dns -->

Maven

Update io.netty:netty-resolver-dns to 4.1.135.Final or later

<!-- Update pom.xml dependency version to 4.1.135.Final for io.netty:netty-resolver-dns -->

After upgrading, run your dependency scanner again to confirm the vulnerability is resolved.

Affected Packages (2)

Affects 1 ecosystem: maven (1).

Package	Ecosystem	Affected	Fixed In
io.netty:netty-resolver-dns	maven	4.2.0.Final, 4.2.1.Final, 4.2.10.Final, 4.2.11.Final (+11 more)	4.2.15.Final
io.netty:netty-resolver-dns	maven	4.1.0.Beta4, 4.1.0.Beta5, 4.1.0.Beta6, 4.1.0.Beta7 (+143 more)	4.1.135.Final

Vulnerability Classification

Common Weakness Enumeration (CWE) identifiers for this vulnerability type.

CWE-345
Insufficient Verification of Data AuthenticityMITRE
CWE-346
Origin Validation ErrorMITRE

CVSS Score Breakdown

What the CVSS (Common Vulnerability Scoring System) 8.7 score means for each attack dimension.

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

None

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

References

Frequently Asked Questions

What is CVE-2026-45674?: Netty Vulnerable to DNS Cache Poisoning via Missing Bailiwick Checks in CNAME Records This vulnerability has been assigned a severity rating of HIGH (CVSS score: 8.7/10).
How do I check if my project is affected by CVE-2026-45674?: CVE-2026-45674 affects io.netty:netty-resolver-dns. Use GeekWala's free vulnerability scanner to check your dependencies against CVE-2026-45674 and 200,000+ other known vulnerabilities.

Severity & Exploitability

CVSS Score

8.7

High exploitability or significant impact. Prioritize remediation within days.

Also Known As

GHSA-676x-f7gg-47vc

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