CVE-2026-11857Public exploit

Local SYSTEM code execution via unsafe Remoting deserialization

Published Jun 17, 2026 · Updated Jun 17, 2026

Insecure deserialization in SCHEMA ST4 on-premises allows local users to execute arbitrary code as SYSTEM through the Client Update Service. The service enables TypeFilterLevel.Full and deserializes crafted objects received through its ST4Updater2 named-pipe and .NET Remoting endpoint. Exploitation requires an authenticated session and local host access; the endpoint is not remotely reachable over the network.

CVSS severity8.4
High
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Insecure deserialization in SCHEMA ST4 on-premises allows local users to execute arbitrary code as SYSTEM through the Client Update Service. The service enables TypeFilterLevel.Full and deserializes crafted objects received through its ST4Updater2 named-pipe and .NET Remoting endpoint. Exploitation requires an authenticated session and local host access; the endpoint is not remotely reachable over the network.

The record

CVE
CVE-2026-11857
Published
Jun 17, 2026
Updated
Jun 17, 2026
Vendor
Quanos Solutions GmbH
Product
SCHEMA ST4
Classifications
CWE-502, CAPEC-586, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 17, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=SCHEMA ST4 on-premises, all versions

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Quanos Solutions GmbH · SCHEMA ST4version=SCHEMA ST4 on-premises, all versions

Published CVSS scores

8.4SEC Consult Vulnerability LabCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data
CAPEC-586Object Injection
T1068Exploitation for Privilege Escalation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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