Summary
Red Hat Wildfly DoS
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.
Impact
Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service. Typical impact: denial of service.
CVE-2016-9589 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (11.0.0.Beta1); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2016-9589? CVE-2016-9589 is a high-severity uncontrolled resource consumption vulnerability in org.wildfly:wildfly-undertow (maven), affecting versions < 11.0.0.Beta1. It is fixed in 11.0.0.Beta1. Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service.
- How severe is CVE-2016-9589? CVE-2016-9589 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of org.wildfly:wildfly-undertow are affected by CVE-2016-9589? org.wildfly:wildfly-undertow (maven) versions < 11.0.0.Beta1 is affected.
- Is there a fix for CVE-2016-9589? Yes. CVE-2016-9589 is fixed in 11.0.0.Beta1. Upgrade to this version or later.
- Is CVE-2016-9589 exploitable, and should I be worried? Whether CVE-2016-9589 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2016-9589 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2016-9589? Upgrade
org.wildfly:wildfly-undertowto 11.0.0.Beta1 or later.