How severe is CVE-2026-45674?

CVE-2026-45674 has a CVSS score of 8.7/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2026-45674?

CVE-2026-45674 affects the following packages: io.netty:netty-resolver-dns (Maven), io.netty:netty-resolver-dns (Maven). Ecosystems affected: Maven.

How do I fix CVE-2026-45674?

Update io.netty:netty-resolver-dns to 4.2.15.Final or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-45674 is resolved across your whole dependency graph.

How do I detect CVE-2026-45674 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for io.netty:netty-resolver-dns, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-45674 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2026-45674 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-45674 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-45674?

CVE-2026-45674 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 22th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-45674?

CVE-2026-45674 is classified as CWE-345 (CWE-345), CWE-346 (CWE-346). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-45674 published, and has it been updated?

CVE-2026-45674 was published on June 12, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

Not in CISA KEV

HIGH severity

CVE-2026-45674 — netty-resolver-dns

HIGH

CVE-2026-45674 is a high-severity (CVSS 8.7) CWE-345 vulnerability in io.netty:netty-resolver-dns. A fix is available for io.netty:netty-resolver-dns — see the affected versions and patch details below.

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

Also known asGHSA-676x-f7gg-47vc

Published

Jun 12, 2026

Updated

Oct 28, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Nov 4, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

A successful exploit gives an attacker total control of the affected component, not partial access.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-45674.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs22th percentile — riskier than 22% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

2 pkgs affected

☕io.netty:netty-resolver-dns☕io.netty:netty-resolver-dns

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

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 Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`io.netty:netty-resolver-dns`	≥ 4.2.0.Final&&< 4.2.15.Final	4.2.15.Final`io.netty:netty-resolver-dns:4.2.15.Final`
☕Maven	`io.netty:netty-resolver-dns`	all versions	4.1.135.Final`io.netty:netty-resolver-dns:4.1.135.Final`

Affected Products

1 product · 2 configurations

Application

nettynetty

≥ 4.2.0 && < 4.2.15

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for io.netty:netty-resolver-dns, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update io.netty:netty-resolver-dns to 4.2.15.Final or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-45674 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant

This Important severity flaw in Netty's DnsResolveContext allows a remote attacker to achieve information disclosure or data manipulation. By crafting malicious DNS responses, an attacker could redirect network traffic or intercept sensitive data, impacting applications utilizing Netty for DNS resolution in Red Hat…

Workaround published by Red Hat

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Source: Red Hat security advisory for CVE-2026-45674 (CC BY 4.0)

Product	Fixed in	Advisory
Cryostat 4 on RHEL 9	`cryostat/cryostat-reports-rhel9:4.2.0-13`	RHSA-2026:48151
Red Hat Build of Apache Camel 3.33.2.SP1	`io.netty/netty-resolver-dns:4.1.135.Final-redhat-00001`	RHSA-2026:26586
Red Hat build of Apache Camel 4.18.1.P1 for Spring Boot 3.5.16	`netty-resolver-dns`	RHSA-2026:37390
Red Hat build of Keycloak 26.4.13	see advisory	RHSA-2026:30049
Red Hat build of Keycloak 26.6.4	see advisory	RHSA-2026:30083
Red Hat build of Quarkus 3.27.4.SP1	`io.netty/netty-resolver-dns:4.1.135.Final-redhat-00001`	RHSA-2026:26018
Red Hat build of Quarkus 3.33.2.SP1	`io.netty/netty-resolver-dns:4.1.135.Final-redhat-00001`	RHSA-2026:26017
Red Hat Data Grid 8.6.2	`netty-resolver-dns`	RHSA-2026:41951

Frequently Asked Questions

### 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

O3 Security · Impact-Aware SCA

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