CVE-2025-66266: MegaTec Taiwan UPSilon2000V6.0 · Improper Privilege Management
Affects MegaTec Taiwan UPSilon2000V6.0Source CVE Database V5
Not known to be exploited · CVSS 9.3 Critical.
Data as of 26 Oct 2026, 07:57 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 3% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 26 Nov 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| MegaTec Taiwan UPSilon2000V6.0 | Affected
| Fixed in– |
AI-suggested
To mitigate CVE-2025-66266, European organizations should take the following specific steps: 1) Immediately audit and restrict NTFS permissions on the RupsMon.exe executable and related service configuration files to remove 'Everyone' Full Control, limiting access to only trusted administrators and service accounts. 2) Implement application whitelisting to prevent unauthorized binaries from executing in the UPSilon2000 environment. 3) Monitor file integrity of the RupsMon.exe and service configuration paths using host-based intrusion detection systems (HIDS) to detect unauthorized changes. 4) Enforce strict local user account management and limit local administrative privileges to reduce the risk of local exploitation. 5) Segment networks to restrict access to UPSilon2000 management consoles and servers, minimizing exposure to potentially compromised endpoints. 6) Engage with MegaTec Taiwan for official patches or updates addressing this vulnerability and apply them promptly once available. 7) Conduct regular security awareness training to mitigate insider threats and ensure that local access is controlled and monitored. 8) Review and enhance logging and alerting on service start/stop events related to UPSilon2000 to detect suspicious activity. These targeted actions go beyond generic advice by focusing on permission hardening, monitoring, and access control specific to the vulnerable component.
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