# CVE-2025-66266

## Summary

- **CVE ID:** CVE-2025-66266
- **Severity:** CRITICAL
- **CVSS Score:** 9.3 (CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N)
- **CWE:** CWE-269
- **Published:** Nov 26, 2025
- **Last Modified:** Mar 13, 2026

## Description

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

## Affected Products

- MegaTec Taiwan — UPSilon2000V6.0 (6.0.5)

## References

- [CNA](https://www.megatec.com.tw/software-download/)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.14%
- **EPSS Percentile:** 3.4

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._