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Improper Privilege ManagementWeakness · CWE-269

CVE-2025-66266

CRITICAL · 9.3 CVSS v4.0 Published 2025-11-26
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
98/100
Remediation priority · Urgent
No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The RupsMon.exe service executable in UPSilon 2000 has overly permissive access controls, granting the 'Everyone' group Full Control permissions. A local authenticated attacker can exploit this by replacing the legitimate executable with a malicious binary or modifying the service configuration path to point to an arbitrary command, then trigger execution by starting/stopping the service to achieve immediate code execution with SYSTEM-level privileges.

MitigationRestrict permissions on RupsMon.exe to remove 'Everyone' Full Control and assign appropriate restrictive ACLs (e.g., Administrators and SYSTEM only). Verify service functionality after permission changes.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
None
Authentication
X
User interaction
None
Scope
X

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Locate the RupsMon.exe service executable
    Search for RupsMon.exe in the UPSilon 2000 installation directory (commonly C:\Program Files\UPSilon2000 or similar). Use: Get-ChildItem -Path "C:\Program Files" -Recurse -Filter "RupsMon.exe" -ErrorAction SilentlyContinue
    Affected if The file exists on the system and is part of an installed UPSilon 2000 deployment
  2. Check file permissions for Everyone group
    Run 'icacls "<path to RupsMon.exe>"' or use PowerShell: (Get-Acl "<path to RupsMon.exe>").Access | Where-Object {$_.IdentityReference -match "Everyone"}
    Affected if The output shows that the 'Everyone' identity has Full Control, Modify, or Write permissions on RupsMon.exe
  3. Verify service configuration and executable path
    Run 'sc qc RupsMon' or use PowerShell: Get-WmiObject Win32_Service -Filter "Name='RupsMon'" | Select-Object Name, PathName, StartName
    Affected if The service points to the RupsMon.exe path and the service runs with elevated privileges (SYSTEM or LocalSystem)
  4. Confirm Everyone permission inheritance
    Check if the Everyone permission is explicitly set on the file or inherited from parent folder: icacls "<path to RupsMon.exe>" | findstr /i "Everyone"
    Affected if Everyone Full Control permissions are present either directly on the file or inherited from the parent directory

A user is affected if RupsMon.exe exists and the Everyone group has Full Control or Modify permissions on the executable, allowing unauthorized modification and privilege escalation via service restart.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Restrict permissions on RupsMon.exe to remove 'Everyone' Full Control and assign appropriate restrictive ACLs (e.g., Administrators and SYSTEM only). Verify service functionality after permission changes.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing1.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,090
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-66266 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
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  • Version or environment caveats, and links to real fixes
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