How severe is GHSA-5pvg-856g-cp85?

GHSA-5pvg-856g-cp85 has a CVSS score of 8.7/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by GHSA-5pvg-856g-cp85?

GHSA-5pvg-856g-cp85 affects the following packages: io.netty:netty-resolver-dns (Maven), io.netty:netty-resolver-dns (Maven). Ecosystems affected: Maven.

How do I fix GHSA-5pvg-856g-cp85?

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 GHSA-5pvg-856g-cp85 is resolved across your whole dependency graph.

How do I detect GHSA-5pvg-856g-cp85 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 GHSA-5pvg-856g-cp85 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 GHSA-5pvg-856g-cp85 actively exploited in the wild?

No public exploit code has been indexed for GHSA-5pvg-856g-cp85 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 GHSA-5pvg-856g-cp85?

GHSA-5pvg-856g-cp85 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 31th 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 GHSA-5pvg-856g-cp85?

GHSA-5pvg-856g-cp85 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 GHSA-5pvg-856g-cp85 published, and has it been updated?

GHSA-5pvg-856g-cp85 was published on June 8, 2026 and was last updated on September 18, 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

Netty has Insufficient Bailiwick Validation for NS RecordsGHSA-5pvg-856g-cp85

HIGH

GHSA-5pvg-856g-cp85 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.

Also known asCVE-2026-47691

Published

Jun 8, 2026

Updated

Sep 18, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Nov 10, 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 GHSA-5pvg-856g-cp85.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk+0.01%

Lower risk than most CVEs31th percentile — riskier than 31% 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 insufficiently validates the bailiwick of NS records, enabling DNS Cache Poisoning. An attacker controlling an authoritative name server for a subdomain can poison the cache for parent domains (like .co.uk).

Details

In io.netty.resolver.dns.DnsResolveContext.AuthoritativeNameServerList#add method accepts any NS record from the AUTHORITY section as long as the record's name is a suffix of the questionName.

This means if the resolver queries evil.co.uk., it will accept an NS record claiming authority over co.uk.. Subsequently, the handleWithAdditional method caches the associated A records from the ADDITIONAL section directly into the authoritativeDnsServerCache under the parent domain's key (co.uk.). This bypasses standard bailiwick rules, where a server authoritative for a subdomain should not be trusted to provide authoritative records for its parent. The poisoned cache is then used for all future resolutions under co.uk..

The io.netty.resolver.dns.DnsResolveContext.AuthoritativeNameServerList#cache method only prevents caching if the record is for the root zone (dots == 1).

Impact

DNS Cache Poisoning. 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 GHSA-5pvg-856g-cp85 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 flaw in Netty's DNS resolution component, `netty-resolver-dns`, allows for DNS cache poisoning. An attacker with control over an authoritative name server for a subdomain could exploit this vulnerability to inject malicious DNS records into the cache of parent domains. This could lead to redirection of…

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 GHSA-5pvg-856g-cp85 (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

UbuntuHIGH

USN-8742-1Ubuntu

Frequently Asked Questions

### Summary Netty's `DnsResolveContext` insufficiently validates the bailiwick of NS records, enabling DNS Cache Poisoning. An attacker controlling an authoritative name server for a subdomain can poison the cache for parent domains (like `.co.uk`). ### Details In `io.netty.resolver.dns.DnsResolveContext.AuthoritativeNameServerList#add` method accepts any NS record from the AUTHORITY section as long as the record's name is a suffix of the questionName. This means if the resolver queries evil.co.uk., it will accept an NS record claiming authority over co.uk.. Subsequently, the `handleWithAddi

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