GHSA-c653-97m9-rcg9 — netty-handler
HIGHGHSA-c653-97m9-rcg9 is a high-severity (CVSS 7.5) CWE-347 vulnerability in io.netty:netty-handler. A fix is available for io.netty:netty-handler — see the affected versions and patch details below.
Netty: Wrapping plain trust manager silently disables hostname verification
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- 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-c653-97m9-rcg9.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
GHSA-c653-97m9-rcg9 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 379,842 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
io.netty:netty-handler☕io.netty:netty-handlerReal-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
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, SimpleTrustManagerFactory.engineGetTrustManagers() and related paths wrap any user-supplied plain X509TrustManager in X509TrustManagerWrapper, which extends X509ExtendedTrustManager but implements the 3-arg checkServerTrusted(chain, authType, SSLEngine) by discarding the SSLEngine and calling the 2-arg delegate. Because the object now IS an X509ExtendedTrustManager, neither SunJSSE's internal AbstractTrustManagerWrapper nor Netty's own OpenSslX509TrustManagerWrapper will re-wrap it to add endpoint-identification. Consequently, even though Netty 4.2 sets endpointIdentificationAlgorithm="HTTPS" by default, a client built with SslContextBuilder.forClient().trustManager(somePlainX509TrustManager) performs no hostname verification at all. Versions 4.1.135.Final and 4.2.15.Final patch the issue.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | io.netty:netty-handler | ≥ 4.2.0.Final&&< 4.2.15.Final | 4.2.15.Finalio.netty:netty-handler:4.2.15.Final |
| ☕Maven | io.netty:netty-handler | all versions | 4.1.135.Finalio.netty:netty-handler:4.1.135.Final |
Affected Products
nettynettyDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for io.netty:netty-handler, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update io.netty:netty-handler to 4.2.15.Final or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-c653-97m9-rcg9 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.
This is an Important flaw in Netty that affects Red Hat products utilizing the `netty-handler` component, including various Red Hat AMQ, Enterprise Application Platform, and OpenShift offerings. The vulnerability arises when a Netty client is configured with a plain X.509 Trust Manager, leading to a bypass of hostname…
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-c653-97m9-rcg9 (CC BY 4.0)
| Product | Fixed in | Advisory |
|---|---|---|
| AMQ Clients 2026.Q3 | netty-handler | RHSA-2026:69459 |
| Cryostat 4 on RHEL 9 | cryostat/cryostat-reports-rhel9:4.2.0-13 | RHSA-2026:48151 |
| Red Hat AMQ Broker 7.13.6 | netty-handler | RHSA-2026:66545 |
| Red Hat AMQ Broker 7.14.1 | netty-handler | RHSA-2026:66488 |
| Red Hat Build of Apache Camel 3.33 for Quarkus 3.33.2.SP1 | netty-handler | RHSA-2026:26586 |
| Red Hat build of Apache Camel 4.18.1.P1 for Spring Boot 3.5.16 | netty-handler | RHSA-2026:37390 |
| Red Hat build of Quarkus 3.27.4.SP1 | netty-handler | RHSA-2026:26018 |
| Red Hat build of Quarkus 3.33.2.SP1 | netty-handler | RHSA-2026:26017 |
Frequently Asked Questions
Is GHSA-c653-97m9-rcg9 in your dependencies?
Find it across Maven, including transitive dependencies.