SYSTEM privilege escalation via mutable placeholder filename
Published Oct 14, 2025 · Updated Oct 14, 2025
TOCTOU race in Microsoft Windows Cloud Files Mini Filter Driver allows local users to gain SYSTEM privileges through placeholder creation. HsmpOpCreatePlaceholders validates a filename in shared user-backed memory, then passes the same mutable buffer to FltCreateFileEx2. Low-privileged access is sufficient to replace the checked name, follow a junction, create a protected DLL, and execute code as SYSTEM.
Summary
What happened
TOCTOU race in Microsoft Windows Cloud Files Mini Filter Driver allows local users to gain SYSTEM privileges through placeholder creation. HsmpOpCreatePlaceholders validates a filename in shared user-backed memory, then passes the same mutable buffer to FltCreateFileEx2. Low-privileged access is sufficient to replace the checked name, follow a junction, create a protected DLL, and execute code as SYSTEM.
The record
- CVE
- CVE-2025-55680
- Published
- Oct 14, 2025
- Updated
- Oct 14, 2025
- Vendor
- Microsoft
- Product
- Windows Server 2019
- Classifications
- CWE-367, CAPEC-29, CAPEC-27, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Oct 14, 2025CVE publishedPublication date reported by the CVE source.
- Oct 14, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=10.0.17763.0 <10.0.17763.7919
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Core Impact Windows Cloud Files Mini Filter Driver exploitfunctional · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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