Code execution via undisclosed input validation flaw
Published Jan 13, 2026 · Updated Jan 13, 2026
Improper input validation in Microsoft SharePoint Server allows local attackers to execute code after user interaction. Microsoft has not disclosed the affected component, accepted input, or validation operation that permits code execution. Exploitation requires a local attack path and user interaction but no prior privileges; success compromises confidentiality, integrity, and availability.
Summary
What happened
Improper input validation in Microsoft SharePoint Server allows local attackers to execute code after user interaction. Microsoft has not disclosed the affected component, accepted input, or validation operation that permits code execution. Exploitation requires a local attack path and user interaction but no prior privileges; success compromises confidentiality, integrity, and availability.
The record
- CVE
- CVE-2026-20951
- Published
- Jan 13, 2026
- Updated
- Jan 13, 2026
- Vendor
- Microsoft
- Product
- Microsoft SharePoint Enterprise Server 2016
- Classifications
- CWE-20, T1203
- Attack vector
- local
- Privileges
- unauthenticated
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=16.0.0 <16.0.5535.1001
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.
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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