CVE-2020-3847
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 · uneditedAn out-of-bounds read was addressed with improved input validation. This issue is fixed in macOS Catalina 10.15.3. A remote attacker may be able to leak memory.
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 · moderate confidenceA memory disclosure vulnerability in macOS Catalina allows remote attackers to read beyond buffer boundaries due to insufficient input validation. The out-of-bounds read enables leaking sensitive memory contents, and the CVSS 9.8 indicates network exploitability with high confidentiality impact.
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< 10.15.3CVSS 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
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/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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Determine installed macOS versionOpen Terminal and run the command: sw_vers -productVersionAffected if The output shows a version number lower than 10.15.3
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Confirm macOS Catalina is runningRun the command: sw_vers -productName to verify the OS nameAffected if The output displays 'macOS Catalina'
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Verify specific minor versionCompare the full version string (such as 10.15.2, 10.15.1, or 10.15.0) against 10.15.3Affected if The version is 10.15.0, 10.15.1, or 10.15.2 (any build prior to 10.15.3)
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Check build number for precisionRun: sw_vers -buildVersion and note the build string for further verification if neededAffected if The build version corresponds to a pre-10.15.3 release
The system is affected if it runs any version of macOS Catalina with a version number lower than 10.15.3, as the out-of-bounds read vulnerability exists in the base OS components of those releases.
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 · scoped10.15.3
Apply macOS Catalina 10.15.3 or later security update to patch the out-of-bounds read vulnerability.
macOS Catalina 10.15.3 or later
- Back up all important data before upgrading the operating system
- Open System Preferences and click on 'Software Update' to check for available updates
- Ensure your Mac is connected to power during the update process
- Install macOS Catalina 10.15.3 or later by following the on-screen prompts
- After installation, verify the macOS version by clicking Apple menu > About This Mac
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation1.0 h
- Implementation2.0 h
- Testing1.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-3847 — 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-2020-3847 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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