CVE-2016-9589 — wildfly-undertow
HIGHCVE-2016-9589 is a high-severity (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in org.wildfly:wildfly-undertow. A fix is available for org.wildfly:wildfly-undertow — see the affected versions and patch details below.
Red Hat Wildfly DoS
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2016-9589 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,333 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
org.wildfly:wildfly-undertowReal-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
Undertow in Red Hat wildfly before version 11.0.0.Beta1 is vulnerable to a resource exhaustion resulting in a denial of service. Undertow keeps a cache of seen HTTP headers in persistent connections. It was found that this cache can easily exploited to fill memory with garbage, up to "max-headers" (default 200) * "max-header-size" (default 1MB) per active TCP connection.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.wildfly:wildfly-undertow | all versions | 11.0.0.Beta1org.wildfly:wildfly-undertow:11.0.0.Beta1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.wildfly:wildfly-undertow, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.wildfly:wildfly-undertow to 11.0.0.Beta1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2016-9589 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.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2016-9589 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2016-9589. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
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.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat JBoss EAP 7 | see advisory | RHSA-2017:0830 |
| Red Hat JBoss EAP 7 | see advisory | RHSA-2017:3456 |
| Red Hat JBoss Enterprise Application Platform 7.0 for RHEL 6 | eap7-activemq-artemis-0:1.1.0-16.SP19_redhat_1.1.ep7.el6 | RHSA-2017:0831 |
| Red Hat JBoss Enterprise Application Platform 7.0 for RHEL 6 | eap7-jboss-ec2-eap-0:7.0.5-1.GA_redhat_1.ep7.el6 | RHSA-2017:0834 |
| Red Hat JBoss Enterprise Application Platform 7.0 for RHEL 7 | eap7-activemq-artemis-0:1.1.0-16.SP19_redhat_1.1.ep7.el7 | RHSA-2017:0832 |
| Red Hat JBoss Enterprise Application Platform 7.1 for RHEL 6 | eap7-activemq-artemis-0:1.5.5.008-1.redhat_1.1.ep7.el6 | RHSA-2017:3454 |
| Red Hat JBoss Enterprise Application Platform 7.1 for RHEL 6 | eap7-jboss-ec2-eap-0:7.1.0-5.GA_redhat_5.ep7.el6 | RHSA-2017:3458 |
| Red Hat JBoss Enterprise Application Platform 7.1 for RHEL 7 | eap7-activemq-artemis-0:1.5.5.008-1.redhat_1.1.ep7.el7 | RHSA-2017:3455 |
Frequently Asked Questions
Is CVE-2016-9589 in your dependencies?
O3 Security finds CVE-2016-9589 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.