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CVE-2025-66631VulnerabilityPublished

CVE-2025-66631: MarimerLLC csla · Deserialization of Untrusted Data

Affects MarimerLLC cslaSource CVE Database V5

0

Not known to be exploited · CVSS 7.2 High : upgrade to 6.0.0 soon.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 4.0 base score
7.2High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.6% chance of exploitation in 30 days – higher than 51% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 6.0.0
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

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 9 Dec 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.

What to do

Upgrade MarimerLLC csla to 6.0.0.

Affected software

ProductAffectedFixed in
NuGetcslapkg:nuget/cslaOther threatsAffected
  • <6.0.0
Fixed in
  • 6.0.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

European organizations should prioritize upgrading all CSLA .NET framework instances to version 6.0.0 or later, where the vulnerability is fixed. If immediate upgrading is not feasible, they should remove the WcfProxy component from data portal configurations to eliminate the attack surface. Conduct thorough code audits and dependency checks to identify all applications using vulnerable CSLA versions. Implement network-level protections such as firewall rules and intrusion detection systems to monitor and restrict access to endpoints exposing WcfProxy services. Employ application-layer input validation and serialization hardening techniques to prevent deserialization of untrusted data. Regularly update and patch all related software components and maintain an inventory of affected assets. Finally, conduct security awareness and incident response training focused on deserialization vulnerabilities and remote code execution threats.

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.

References

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