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Mac Os XOperating system · Apple

CVE-2021-30981

HIGH · 7.8 CVSS v3.1 Published 2021-08-24
Fix available
A fix is available. Upgrade to 10.15.7 / 11.6.2 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
A buffer overflow was addressed with improved bounds checking. This issue is fixed in macOS Monterey 12.1, Security Update 2021-008 Catalina, macOS Big Sur 11.6.2. An application may be able to execute arbitrary code with kernel 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 buffer overflow vulnerability in macOS that allows a local application to escalate privileges and execute arbitrary code with kernel-level privileges. The issue was addressed with improved bounds checking in the affected component.

MitigationApply the available Apple security updates: macOS Monterey 12.1, Security Update 2021-008 for Catalina, or macOS Big Sur 11.6.2, depending on the installed OS version.

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:>= 10.15, < 10.15.7= 10.15.7
macOSOperating system
Affected:>= 11.0, < 11.6.2>= 12.0, < 12.1

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 to view the macOS version number
    Affected if The version displayed is below 10.15.7, or falls between 11.0 and 11.6.1, or falls between 12.0 and 12.0.x (prior to 12.1)
  2. Confirm full version build number
    Run 'sw_vers -buildVersion' to get the exact build, which helps distinguish between minor patch levels within the same major version
    Affected if The build number corresponds to an unpatched release of the affected version range
  3. Identify macOS marketing name
    Run 'sw_vers -productName' or check System Preferences > About to see if the system is running Catalina (10.15), Big Sur (11.x), or Monterey (12.x)
    Affected if The system is running an older, unpatched release of any of these three macOS generations within the affected version ranges
  4. Verify patch status via system update
    Check System Preferences > Software Update or run 'softwareupdate --list' to see if any pending security updates are available
    Affected if A security update is available but has not been installed, indicating the system likely remains vulnerable

The system is affected if it runs macOS 10.15.x before 10.15.7, macOS 11.x before 11.6.2, or macOS 12.x before 12.1 and has not received the corresponding security patch.

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 10.15.7 / 11.6.2 / 12.1 or later
Fixed in 10.15.711.6.212.1
Interim mitigation

Apply the available Apple security updates: macOS Monterey 12.1, Security Update 2021-008 for Catalina, or macOS Big Sur 11.6.2, depending on the installed OS version.

Recommended fix High confidence

macOS Monterey 12.1, macOS Big Sur 11.6.2, or Security Update 2021-008 for Catalina

  1. Back up all important data before performing any system update
  2. Check the current macOS version by clicking Apple menu > About This Mac
  3. For macOS 10.15.x (Catalina) users: Install Security Update 2021-008 Catalina via System Preferences > Software Update
  4. For macOS 11.x (Big Sur) users: Update to macOS Big Sur 11.6.2 via System Preferences > Software Update
  5. For macOS 12.x (Monterey) users: Update to macOS Monterey 12.1 via System Preferences > Software Update
  6. After updating, verify the fix by checking that the kernel version includes the security patch
Caveat Major macOS updates may have compatibility issues with older applications; verify software and hardware compatibility before upgrading

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

Fix this in Mac Os X Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
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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-2021-30981 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