What is CVE-2017-3203?

CVE-2017-3203 is a high-severity insecure deserialization vulnerability in org.springframework.flex:spring-flex (maven), affecting versions <= 1.5.2.RELEASE. No fixed version is listed yet. Untrusted serialized data is processed by a deserializer that can instantiate arbitrary objects or execute code as a side effect.

How severe is CVE-2017-3203?

CVE-2017-3203 has a CVSS score of 8.1 (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.springframework.flex:spring-flex are affected by CVE-2017-3203?

org.springframework.flex:spring-flex (maven) versions <= 1.5.2.RELEASE is affected.

Is there a fix for CVE-2017-3203?

No fixed version is listed for CVE-2017-3203 yet. Monitor the advisory for updates and apply mitigations in the interim.

Is CVE-2017-3203 exploitable, and should I be worried?

Whether CVE-2017-3203 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.

What actually determines whether CVE-2017-3203 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.

CVE-2017-3203

Q: How severe is CVE-2017-3203?

CVE-2017-3203 has a CVSS score of 8.1 (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.

Q: Which versions of org.springframework.flex:spring-flex are affected by CVE-2017-3203?

org.springframework.flex:spring-flex (maven) versions <= 1.5.2.RELEASE is affected.

Q: Is there a fix for CVE-2017-3203?

No fixed version is listed for CVE-2017-3203 yet. Monitor the advisory for updates and apply mitigations in the interim.

Q: Is CVE-2017-3203 exploitable, and should I be worried?

Whether CVE-2017-3203 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.

Q: What actually determines whether CVE-2017-3203 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.

Q: How do I fix CVE-2017-3203?

No fixed version is listed yet. In the interim: Avoid deserializing data from untrusted sources. If deserialization is required, use a format that does not support code execution and validate the input strictly.

Summary

Deserialization of Untrusted Data in Spring-flex

The Java implementations of AMF3 deserializers in Pivotal/Spring Spring-flex derive class instances from java.io.Externalizable rather than the AMF3 specification's recommendation of flash.utils.IExternalizable. A remote attacker with the ability to spoof or control an RMI server connection may be able to send serialized Java objects that execute arbitrary code when deserialized.

Impact

Untrusted serialized data is processed by a deserializer that can instantiate arbitrary objects or execute code as a side effect. Typical impact: arbitrary code execution or logic abuse.

CVE-2017-3203 has a CVSS score of 8.1 (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. No fixed version is listed yet, so configuration controls and monitoring matter more in the interim.

Affected versions

org.springframework.flex:spring-flex (<= 1.5.2.RELEASE)

Security releases

Not available

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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Remediation advice

No fixed version is listed for CVE-2017-3203 yet.

In the interim: Avoid deserializing data from untrusted sources. If deserialization is required, use a format that does not support code execution and validate the input strictly.

Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.

Frequently Asked Questions

What is CVE-2017-3203? CVE-2017-3203 is a high-severity insecure deserialization vulnerability in org.springframework.flex:spring-flex (maven), affecting versions <= 1.5.2.RELEASE. No fixed version is listed yet. Untrusted serialized data is processed by a deserializer that can instantiate arbitrary objects or execute code as a side effect.
How severe is CVE-2017-3203? CVE-2017-3203 has a CVSS score of 8.1 (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.springframework.flex:spring-flex are affected by CVE-2017-3203? org.springframework.flex:spring-flex (maven) versions <= 1.5.2.RELEASE is affected.
Is there a fix for CVE-2017-3203? No fixed version is listed for CVE-2017-3203 yet. Monitor the advisory for updates and apply mitigations in the interim.
Is CVE-2017-3203 exploitable, and should I be worried? Whether CVE-2017-3203 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-2017-3203 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-2017-3203? No fixed version is listed yet. In the interim: Avoid deserializing data from untrusted sources. If deserialization is required, use a format that does not support code execution and validate the input strictly.