Insecure SYSTEM Service Permissions in UPSilon2000V6.0 (RupsMon.exe) leading to trivial Local Privilege Escalation
Priority MEDIUM 41CWE-269Published · Updated
Key facts
- Attack vector
- Local
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Privilege escalation
- 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-269.
Summary
The RupsMon.exe service executable in UPSilon 2000 has insecure permissions, allowing the 'Everyone' group Full Control. A local attacker can replace the executable with a malicious binary to execute code with SYSTEM privileges or simply change the config path of the service to a command; starting and stopping the service to immediately achieve code execution and privilege escalation
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00146 3rd percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet
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 |
|---|---|---|---|---|---|
| MegaTec Taiwan | UPSilon2000V6.0 | 6.0.5 | — | No fix listed | CNA |
- UPSilon2000V6.0 VendorMegaTec Taiwan Affected 6.0.5 Fixed in — No fix listed CNA
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2025-66266
- 2026-10-03 Alias added: GHSA-9553-998g-436x
References
More MegaTec Taiwan vulnerabilities
- TI-2025-40746 Unquoted Service path in UPSilon2000V6.0 SYSTEM privilege service CVSS 4.0HIGH 7.2
- TI-2025-40749 Unquoted Service Path in UPSilon2000V6.0(RupsMon and USBMate) running as SYSTEM CVSS 4.0HIGH 7.1
- TI-2025-40747 Insecure permissions in configuration directory (C:\\usr) CVSS 4.0MEDIUM 6.9
Sources
- CVE-2025-66266 · CVE Program
- CVE-2025-66266 · NVD
- FIRST EPSS
- GHSA-9553-998g-436x · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences