How severe is CVE-2025-66631?

CVE-2025-66631 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2025-66631 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (43rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-66631?

CVE-2025-66631 affects Cslanet Csla .net. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-66631?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2025-66631 have an EU (EUVD) identifier?

Yes. CVE-2025-66631 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-201825.

When was CVE-2025-66631 published?

CVE-2025-66631 was published on 2025-12-09 and last updated on 2026-06-17.

CVE-2025-66631

CVE-2025-66631 is a critical-severity vulnerability in Cslanet Csla .net with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-502.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v4: 7.2
EPSS exploit prediction: 1% (43rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-201825
Weakness: CWE-502
Affected product: Cslanet Csla .net
Published: 2025-12-09
Last modified: 2026-06-17

Description

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. This vulnerability is fixed in version 6.0.0. To workaround this issue, remove the WcfProxy in data portal configurations.

Frequently asked questions

What is CVE-2025-66631?: 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. This vulnerability is fixed in version 6.0.0. To workaround this issue, remove the WcfProxy in data portal configurations.
How severe is CVE-2025-66631?: CVE-2025-66631 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2025-66631 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (43rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-66631?: CVE-2025-66631 affects Cslanet Csla .net. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-66631?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2025-66631 have an EU (EUVD) identifier?: Yes. CVE-2025-66631 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-201825.
When was CVE-2025-66631 published?: CVE-2025-66631 was published on 2025-12-09 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:cslanet:csla_.net:*:*:*:*:*:*:*:*

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