Description
Quanos SCHEMA ST4 on-premises contains a local privilege escalation vulnerability in the Client Update Service due to insecure deserialization in the .NET Remoting service. The service is configured with TypeFilterLevel.Full and is bound to local interfaces only through named pipes. A local authenticated attacker can connect to the local named pipe, obtain the .NET Remoting endpoint, and send specially crafted serialized objects. Successful exploitation results in arbitrary code execution in the context of the update process with NT AUTHORITY\SYSTEM privileges. Network-only exploitation is not possible and local host access with an authenticated user session is required.
Published: 2026-06-17
Score: 8.4 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Impact

The vulnerability arises from insecure deserialization in the .NET Remoting client update service of Quanos SCHEMA ST4. Because the service is configured with TypeFilterLevel.Full and accesses only local named pipes, a local authenticated attacker can craft and send malicious serialized objects to the update endpoint. When successful, the code executes with NT AUTHORITY\SYSTEM privileges, giving the attacker full system control on the host.

Affected Systems

Quanos Solutions GmbH SCHEMA ST4 on-premises installations are affected. No specific product versions are listed. The cloud/SaaS deployment is not impacted.

Risk and Exploitability

With a CVSS score of 8.4 the vulnerability is rated as high severity, yet the EPSS score is unavailable and the vulnerability is not listed in the CISA KEV catalog. Attackers must have local host access and an authenticated user session; remote network-only exploitation is not possible. Consequently, the risk is mitigated in environments that enforce least privilege and restrict local interactive access.

Generated by OpenCVE AI on June 18, 2026 at 11:59 UTC.

Remediation

Vendor Solution

The vendor does not provide a patch. The vendor recommends disabling the affected Client Update Service. Updating the client is then only possible manually with a privileged user account. Quanos confirms that exploitation requires local host access with an authenticated user session. In properly managed environments following the Least Privilege principle, the attack surface is significantly reduced. Quanos Cloud/SaaS deployments are not affected. Quanos considers the migration to the Cloud/SaaS architecture the strategic long-term solution.

Vendor Workaround

Disable the Client Update Service until a fix is provided. Restrict local interactive access to systems running SCHEMA ST4 on-premises. Apply the principle of least privilege to local user accounts and prevent untrusted users from obtaining local sessions on affected hosts.

OpenCVE Recommended Actions

  • Disable the Client Update Service until a vendor patch becomes available
  • Restrict local interactive access to systems running SCHEMA ST4 on-premises
  • Apply the principle of least privilege to local user accounts and prevent untrusted users from obtaining local sessions
  • Consider migrating to the Quanos Cloud/SaaS architecture as a long‑term strategy

Generated by OpenCVE AI on June 18, 2026 at 11:59 UTC.

Tracking

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Advisories

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References
Link Providers
https://r.sec-consult.com/quanos cve-icon
History

Sun, 21 Jun 2026 09:45:00 +0000

Type Values Removed Values Added
First Time appeared Quanos Solutions
Quanos Solutions schema St4
Vendors & Products Quanos Solutions
Quanos Solutions schema St4

Thu, 18 Jun 2026 04:45:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Wed, 17 Jun 2026 12:45:00 +0000

Type Values Removed Values Added
Description Quanos SCHEMA ST4 on-premises contains a local privilege escalation vulnerability in the Client Update Service due to insecure deserialization in the .NET Remoting service. The service is configured with TypeFilterLevel.Full and is bound to local interfaces only through named pipes. A local authenticated attacker can connect to the local named pipe, obtain the .NET Remoting endpoint, and send specially crafted serialized objects. Successful exploitation results in arbitrary code execution in the context of the update process with NT AUTHORITY\SYSTEM privileges. Network-only exploitation is not possible and local host access with an authenticated user session is required.
Title Insecure .NET Remoting deserialization in Quanos SCHEMA ST4 Client Update Service allows local privilege escalation
Weaknesses CWE-502
References
Metrics cvssV4_0

{'score': 8.4, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N'}

Subscriptions

Quanos Solutions Schema St4
cve-icon MITRE

Status: PUBLISHED

Assigner: SEC-VLab

Published:

Updated: 2026-06-17T14:56:58.522Z

Reserved: 2026-06-10T09:08:22.916Z

Link: CVE-2026-11857

cve-icon Vulnrichment

Updated: 2026-06-17T14:56:44.840Z

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-06-20T23:03:29Z

Weaknesses
  • CWE-502

    Deserialization of Untrusted Data