dbcve.org
Mac Os XOperating system · Apple

CVE-2021-1839

HIGH · 7.8 CVSS v3.1 Published 2021-09-08
Fix available
A fix is available. Upgrade to 11.3 or later.
See remediation →
80/100
Remediation priority · High
Zero-click

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 · unedited
The issue was addressed with improved permissions logic. This issue is fixed in macOS Big Sur 11.3, Security Update 2021-002 Catalina, Security Update 2021-003 Mojave. A local attacker may be able to elevate their privileges.

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 confidence

A local privilege escalation vulnerability in macOS related to permissions logic. A local attacker with standard user access could potentially elevate to higher privileges by exploiting improper permission handling. This affects macOS Catalina and Mojave (Security Updates 2021-002/2021-003) and macOS Big Sur 11.3 and prior.

MitigationApply the available security updates: macOS Big Sur 11.3 or later, Security Update 2021-002 for Catalina, or Security Update 2021-003 for Mojave. Verify the update is installed via System Preferences > Software Update.

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
Mac Os XOperating system
Affected:= 10.14= 10.14.0= 10.14.1= 10.14.2= 10.14.3= 10.14.4= 10.14.5= 10.14.6= 10.15= 10.15.1= 10.15.2= 10.15.3
macOSOperating system
Affected:>= 11.0, < 11.3

CVSS 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
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/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 checks

Work through these to decide whether this CVE applies to you.

  1. Check installed macOS version
    Run `sw_vers -productVersion` in Terminal or open System Preferences > About
    Affected if Version is 10.14.x, 10.15.x, or 11.0-11.2.x (all versions prior to the fixed releases)
  2. Verify Big Sur update status
    If running macOS 11.x, check if version is 11.3 or later by running `sw_vers -productVersion`
    Affected if Version is 11.0, 11.1, 11.2, or 11.2.1 (all versions before 11.3)
  3. Verify Catalina security update
    If running macOS 10.15.x, check System Preferences > Software Update or run `system_profiler SPSoftwareDataType` to confirm Security Update 2021-002 is installed
    Affected if Running 10.15.x without Security Update 2021-002 installed
  4. Verify Mojave security update
    If running macOS 10.14.x, check System Preferences > Software Update or run `system_profiler SPSoftwareDataType` to confirm Security Update 2021-003 is installed
    Affected if Running 10.14.x without Security Update 2021-003 installed

You are affected if your macOS version is 10.14.x, 10.15.x, or 11.0-11.2.x and the corresponding security update (2021-003 for Mojave, 2021-002 for Catalina) or macOS 11.3 has not been installed.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Upgrade available Upgrade to 11.3 or later
Fixed in 11.3
Interim mitigation

Apply the available security updates: macOS Big Sur 11.3 or later, Security Update 2021-002 for Catalina, or Security Update 2021-003 for Mojave. Verify the update is installed via System Preferences > Software Update.

Recommended fix High confidence

macOS Big Sur 11.3 or later / Security Update 2021-002 (Catalina) / Security Update 2021-003 (Mojave)

  1. Identify the current macOS version by clicking Apple menu > About This Mac
  2. If running macOS Big Sur 11.0-11.2.x: Upgrade to macOS Big Sur 11.3 or later via System Preferences > Software Update
  3. If running macOS 10.15.x (Catalina): Apply Security Update 2021-002 Catalina via System Preferences > Software Update
  4. If running macOS 10.14.x (Mojave): Apply Security Update 2021-003 Mojave via System Preferences > Software Update
  5. Restart the device after applying the update
Caveat Standard security update risks apply - ensure backup of critical data before updating, and verify compatibility of essential applications with the new version

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Mac Os X Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing1.0 h
  • Review / QA1.0 h
5.0 hours of engineering $890
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Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-1839 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • 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