Raw vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2025-66631 is a high-severity Deserialization of Untrusted Data (CWE-502) vulnerability in Cslanet Csla .Net. Its CVSS base score is 7.2 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked in the top 48% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2025-66631 is a remote code execution vulnerability in the CSLA .NET framework, which is designed for developing reusable, object-oriented business layers in applications. The issue affects versions 5.5.4 and below, specifically in the WcfProxy component. WcfProxy relies on the now-obsolete NetDataContractSerializer (NDCS) for deserialization, making it susceptible to exploitation during this process. The vulnerability is classified under CWE-502 (Deserialization of Untrusted Data) and carries a CVSS 3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).
Any unauthenticated attacker with network access can exploit this vulnerability by sending maliciously crafted serialized data to a vulnerable CSLA .NET application using WcfProxy. The attack requires low complexity and no user interaction, allowing remote code execution on the target system. Successful exploitation enables attackers to achieve high impacts on confidentiality, integrity, and availability, potentially compromising the entire application server.
Mitigation is available in CSLA .NET version 6.0.0, which addresses the vulnerability. As a workaround, remove WcfProxy from data portal configurations. Additional details are provided in the GitHub security advisory (GHSA-wq34-7f4g-953v), issue tracker (#4001), and pull request (#4018).
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-201825
Vulnerability Data
CSLA .NET is a framework designed for the development of reusable, object-oriented business layers for applications. Versions 5.5.4 and below allow the use of WcfProxy. WcfProxy uses the now-obsolete NetDataContractSerializer (NDCS) and is vulnerable to remote code execution during deserialization.…
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This vulnerability is fixed in version 6.0.0. To workaround this issue, remove the WcfProxy in data portal configurations.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation can uncover deserialization flaws before deployment.
Input validation directly stops deserialization of untrusted data by ensuring inputs are valid before processing.
Engineering principles such as safe deserialization and input sanitization structurally prevent the weakness from being introduced.
Integrity verification tools can detect malformed or tampered serialized data after the fact.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing includes validation of deserialization routines and the use of untrusted data, reducing the likelihood that unsafe object reconstruction will be deployed.
Requiring vetted libraries, regular updates and SAST before release reduces the likelihood that deserialization logic will accept and act on attacker-controlled serialized objects.
Regular scanning of third-party libraries and timely patching reduce the likelihood that unsafe deserialization vulnerabilities remain active.