CVE-2020-1020
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 · uneditedA remote code execution vulnerability exists in Microsoft Windows when the Windows Adobe Type Manager Library improperly handles a specially-crafted multi-master font - Adobe Type 1 PostScript format.For all systems except Windows 10, an attacker who successfully exploited the vulnerability could execute code remotely, aka 'Adobe Font Manager Library Remote Code Execution Vulnerability'. This CVE ID is unique from CVE-2020-0938.
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 confidenceA remote code execution vulnerability exists in the Windows Adobe Type Manager Library when it improperly handles specially-crafted multi-master fonts in Adobe Type 1 PostScript format. An attacker could exploit this by enticing a user to open a maliciously crafted font file, potentially allowing arbitrary code execution with user privileges.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE dataall versionsall versionsall versionsall versionsall versionsall versionsall versionsall versionsCVSS 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
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
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 checksWork through these to decide whether this CVE applies to you.
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Check Windows versionRun 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to identify the installed Windows versionAffected if The version is Windows 7 (any version) or Windows 10 1507, 1607, 1709, 1803, 1809, 1903, or 1909
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Verify Adobe Type Manager Library presenceCheck if atmfd.dll exists in the system. Search for the file at %SystemRoot%\System32\atmfd.dll or check the registry at HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\SubSystems\Windows for 'atmfd.dll' referenceAffected if The atmfd.dll file or its registry reference exists on the system, indicating the vulnerable component is present
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Check for Type 1 font handling enabledExamine registry key HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Fonts for entries marked as 'Type 1' or inspect the registry key HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Compatibility32\00 for 'atmfd' value. Also check HKLM\SYSTEM\CurrentControlSet\Services\FontCache for the Font Cache service statusAffected if Type 1 fonts are registered in the system and the font handling subsystem is active and accessible to user-mode applications
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Confirm user access to font filesVerify if users have permissions to open or load font files from user-accessible locations such as the Fonts folder, downloaded files, or network shares. Check folder permissions on %SystemRoot%\Fonts and user profile font directoriesAffected if Standard users can open, preview, or install font files without administrative restrictions, allowing potential exploitation
A system is likely affected if it runs an affected Windows version (Windows 7 through Windows 10 1909), has the Adobe Type Manager Library (atmfd.dll) present, and allows users to access or open font files.
Generated from the published advisory. Verify against your own configuration.
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.
dbcve · scopedApply the Microsoft security update (MS20-027) to patch the Adobe Type Manager Library vulnerability. Until patched, avoid opening untrusted font files and consider disabling the ATMFD.dll driver as an additional workaround.
Install Microsoft Windows April 2020 Security Updates (KB4551762 for Windows 10 1909/1903, KB4550969 for Windows 10 1809, KB4549949 for Windows 10 1803, and corresponding updates for other affected versions)
- Open Windows Update by pressing the Windows key and typing 'Windows Update', then press Enter
- Click 'Check for updates' to scan for available updates
- Install all recommended security updates, particularly the April 2020 security updates that address this vulnerability
- Restart the computer if prompted to complete the installation
- Verify the update was installed by viewing update history or checking installed updates
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation6.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-1020 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2020-1020 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data