Missing authorization in Quanos SCHEMA ST4 Client Update Service allows arbitrary file overwrite as SYSTEM
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- High · High · None
- Fix status
- No fix listed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-862.
Summary
Quanos SCHEMA ST4 on-premises contains a local privilege escalation vulnerability in the Client Update Service. The update service runs as NT AUTHORITY\SYSTEM and exposes a .NET Remoting interface over a named pipe without sufficient access controls or authorization. A local authenticated low-privileged user can connect to the interface and invoke privileged update methods such as Update(). This allows arbitrary file write and delete operations with SYSTEM privileges and can be used to achieve local privilege escalation.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Quanos Solutions GmbH | SCHEMA ST4 | SCHEMA ST4 on-premises, all versions and later | — | No fix listed | CNA |
- SCHEMA ST4 VendorQuanos Solutions GmbH Affected SCHEMA ST4 on-premises, all versions and later Fixed in — No fix listed CNA
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2026-11858
- 2026-10-03 Alias added: GHSA-62mq-g5fg-59fx
References
Advisory 1
More Quanos Solutions GmbH vulnerabilities
- TI-2026-10232 Insecure .NET Remoting deserialization in Quanos SCHEMA ST4 Client Update Service allows local privilege escalation CVSS 4.0HIGH 8.4
Sources
- CVE-2026-11858 · CVE Program
- CVE-2026-11858 · NVD
- FIRST EPSS
- GHSA-62mq-g5fg-59fx · GitHub Advisory Database · CC BY 4.0
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