Summary
Csla affected by Remote Code Execution via WcfProxy (NetDataContractSerializer)
Workarounds
If you are using a version CSLA .NET older than version 6, you should stop using WcfProxy in your data portal configuration. Doing this avoids the use of WCF and the NetDataContractSerializer, avoiding the vulnerability.
Impact
Versions of CSLA .NET prior to version 6 allow the use of WcfProxy. WcfProxy uses the NetDataContractSerializer (NDCS) which has known vulnerabilities that can allow remote execution of code during deserialization. NDCS itself is considered obsolete, and you should avoid using WcfProxy or upgrade to CSLA 6 or higher where this issue does not exist.
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.
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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CSLA .NET version 6 and higher do not use WCF or NetDataContractSerializer.
Frequently Asked Questions
- What is CVE-2025-66631? CVE-2025-66631 is a high-severity insecure deserialization vulnerability in Csla (nuget), affecting versions < 6.0.0. It is fixed in 6.0.0. Untrusted serialized data is processed by a deserializer that can instantiate arbitrary objects or execute code as a side effect.
- Which versions of Csla are affected by CVE-2025-66631? Csla (nuget) versions < 6.0.0 is affected.
- Is there a fix for CVE-2025-66631? Yes. CVE-2025-66631 is fixed in 6.0.0. Upgrade to this version or later.
- Is CVE-2025-66631 exploitable, and should I be worried? Whether CVE-2025-66631 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-2025-66631 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-2025-66631? Upgrade
Cslato 6.0.0 or later.