Compliance Impact

The provided information does not explicitly address how the CVE-2026-11857 vulnerability affects compliance with common standards and regulations such as GDPR or HIPAA.

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Executive Summary

CVE-2026-11857 is a local privilege escalation vulnerability in Quanos SCHEMA ST4 on-premises. It arises from insecure deserialization in the .NET Remoting service, which is configured with TypeFilterLevel.Full and bound only to local interfaces via named pipes.

A local authenticated attacker can connect to the local named pipe, access the .NET Remoting endpoint, and send specially crafted serialized objects. This allows the attacker to execute arbitrary code with NT AUTHORITY\SYSTEM privileges, effectively gaining full control over the system.

Exploitation requires local host access with an authenticated user session; it cannot be exploited remotely over the network.

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Impact Analysis

This vulnerability allows a local authenticated attacker to escalate their privileges to SYSTEM level by executing arbitrary code within the update process context.

With SYSTEM privileges, the attacker can perform any action on the affected system, including modifying or deleting files, installing malware, or disrupting services.

Because exploitation requires local access, the risk is primarily from insiders or attackers who have already gained some level of access to the host.

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Detection Guidance

This vulnerability affects the local Client Update Service of Quanos SCHEMA ST4 on-premises installations, which uses .NET Remoting bound to local named pipes. Detection involves verifying if the vulnerable Client Update Service is running on the system.

Since exploitation requires local authenticated access and interaction with named pipes, you can check for the presence of the named pipe endpoints related to the Client Update Service and monitor for unusual or unauthorized connections to these pipes.

Suggested commands to detect the vulnerable service and named pipes include:

• On Windows, use `sc query` or `Get-Service` PowerShell cmdlet to check if the Client Update Service is running.
• Use `handle.exe` from Sysinternals or PowerShell scripts to list named pipes and identify those related to the Client Update Service.
• Monitor event logs and audit logs for suspicious access to named pipes or unexpected process executions with elevated privileges.

Note that network detection is not applicable since the service is bound to local interfaces only and exploitation requires local authenticated access.

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Mitigation Strategies

The vendor Quanos does not provide a patch for this vulnerability yet.

As an immediate mitigation, it is recommended to disable the affected Client Update Service to prevent exploitation.

Additionally, conduct a thorough security review of the product deployment to identify and address any other potential security issues.

Since exploitation requires local authenticated access, restricting user permissions and monitoring local user activities can also help reduce risk.

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