Code execution via malformed BlendDesignPositions arrays
Published Apr 15, 2020 · Updated Oct 21, 2025
Out-of-bounds write in Microsoft Windows Adobe Type Manager Library allows attackers to execute code via a crafted Type 1 font. The SetBlendDesignPositions handler accepts more than 16 position arrays and writes them past a fixed 16-entry stack buffer. Exploitation requires Windows to process the font with user interaction; Windows 10 confines execution to an AppContainer, while earlier releases expose kernel-mode execution.
Summary
What happened
Out-of-bounds write in Microsoft Windows Adobe Type Manager Library allows attackers to execute code via a crafted Type 1 font. The SetBlendDesignPositions handler accepts more than 16 position arrays and writes them past a fixed 16-entry stack buffer. Exploitation requires Windows to process the font with user interaction; Windows 10 confines execution to an AppContainer, while earlier releases expose kernel-mode execution.
The record
- CVE
- CVE-2020-0938
- Published
- Apr 15, 2020
- Updated
- Oct 21, 2025
- Vendor
- Microsoft
- Product
- Windows 10 Version 1909
- Classifications
- CWE-787, T1203
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Apr 15, 2020CVE publishedPublication date reported by the CVE source.
- Nov 3, 2021Exploitation reportedCISA Known Exploited Vulnerabilities entry
- Oct 21, 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?
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- Affected versionversion=unspecified
What conditions does exploitation require?
What is affected?
Published CVSS scores
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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
- Project Zero BlendDesignPositions proof of conceptproof of concept · demonstrated
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Reported exploitation
- Project Zero in-the-wild Windows font exploit analysisreported exploitation
- CISA Known Exploited Vulnerabilities entryknown exploited catalog
Technologies
Your stack
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Your stack
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