Host information disclosure across guest boundary
Published Jan 13, 2026 · Updated Jan 13, 2026
Improper access control in Windows Hyper-V on affected Windows releases allows guest OS users to disclose host information locally. Microsoft identifies the exposed boundary as Guest VM to Hyper-V host server but has not published the faulty component, operation, or data type. Exploitation requires high privileges in a guest VM; the reported consequence is host-side information disclosure without integrity or availability impact.
Summary
What happened
Improper access control in Windows Hyper-V on affected Windows releases allows guest OS users to disclose host information locally. Microsoft identifies the exposed boundary as Guest VM to Hyper-V host server but has not published the faulty component, operation, or data type. Exploitation requires high privileges in a guest VM; the reported consequence is host-side information disclosure without integrity or availability impact.
The record
- CVE
- CVE-2026-20825
- Published
- Jan 13, 2026
- Updated
- Jan 13, 2026
- Vendor
- Microsoft
- Product
- Windows Server 2019
- Classifications
- CWE-284
- Attack vector
- local
- Privileges
- admin
Timeline
How it unfolded
- Jan 13, 2026CVE publishedPublication date reported by the CVE source.
- Jan 13, 2026Record 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 <10.0.17763.8276
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
No public exploit references are available in this record.
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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