CVE-2020-27942
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 logic issue was addressed with improved state management. This issue is fixed in Security Update 2021-002 Catalina, Security Update 2021-003 Mojave. Processing a maliciously crafted font file may lead to arbitrary code execution.
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 logic vulnerability in macOS font processing allows arbitrary code execution when processing a maliciously crafted font file. The issue stems from improper state management in the font parsing subsystem, which can be exploited to hijack execution flow. This affects both macOS Catalina and Mojave.
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 data>= 10.14, <= 10.14.5>= 10.15, <= 10.15.5= 10.14.6= 10.15.6= 10.15.7CVSS 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
- Local
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/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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Identify installed macOS versionRun `sw_vers -productVersion` in Terminal or check System Preferences > AboutAffected if Version is 10.14.0-10.14.5, 10.14.6, 10.15.0-10.15.5, 10.15.6, or 10.15.7 (unpatched)
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Confirm macOS variant is Mojave or CatalinaRun `sw_vers -productVersion` and note the major.minor version (10.14 = Mojave, 10.15 = Catalina)Affected if Major version is 10.14 or 10.15
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Verify patch state if on 10.14.6 or 10.15.7Check if Security Update 2021-003 (Mojave) or 2021-002 (Catalina) has been installed via System Preferences > Software UpdateAffected if Running 10.14.6 without Security Update 2021-003, or 10.15.7 without Security Update 2021-002
The system is affected if it runs any unpatched version of macOS Mojave (10.14.x) or Catalina (10.15.x) within the ranges listed, as the vulnerability exists in the font parsing subsystem and can be triggered by processing a malicious font file.
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 relevant Apple Security Update (2021-002 for Catalina or 2021-003 for Mojave) to all affected systems. Avoid opening or processing untrusted font files from unknown sources.
Apply Security Update 2021-003 Mojave or Security Update 2021-002 Catalina (depending on your macOS version)
- 1. Back up your Mac using Time Machine or another backup solution before applying updates
- 2. Go to System Preferences > Software Update (or System Preferences > App Store on older macOS)
- 3. Check for available updates
- 4. Locate and install Security Update 2021-003 (for macOS Mojave 10.14.6) or Security Update 2021-002 (for macOS Catalina 10.15.6)
- 5. Restart your Mac when prompted to complete the installation
- 6. After restarting, verify the update was applied by returning to Software Update and confirming no additional security updates are available
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-2020-27942 — 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-2020-27942 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
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