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Mac Os XOperating system · Apple

CVE-2021-30688

HIGH · 8.8 CVSS v3.1 Published 2021-09-08
Fix available
A fix is available. Upgrade to 11.4 or later.
See remediation →
90/100
Remediation priority · Urgent
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 malicious application may be able to break out of its sandbox. This issue is fixed in macOS Big Sur 11.4, Security Update 2021-003 Catalina. A path handling issue was addressed with improved validation.

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 confidence

A sandbox escape vulnerability in macOS where a malicious application could break out of its sandbox due to insufficient path validation. The issue was addressed with improved path validation in macOS Big Sur 11.4 and Security Update 2021-003 for Catalina.

MitigationApply the vendor-supplied security updates: macOS Big Sur 11.4 or later, or Security Update 2021-003 for macOS Catalina. Alternatively, upgrade to the latest supported macOS version to receive current security patches.

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, <= 10.15.6= 10.15.7
macOSOperating system
Affected:>= 11.0, < 11.4

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
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/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. Determine your macOS version
    Open Terminal and run: sw_vers -productVersion
    Affected if The version shows 10.15, 10.15.1, 10.15.2, 10.15.3, 10.15.4, 10.15.5, 10.15.6, or any 11.0 through 11.3.x (versions below 10.15.7 on Catalina or below 11.4 on Big Sur)
  2. Check if running macOS Catalina (10.15.x)
    If the version from step 1 begins with 10.15, run: defaults read /System/Library/CoreServices/SystemVersion ProductVersionExtraString
    Affected if The system shows macOS 10.15.7 without Security Update 2021-003 installed, or any version 10.15.0 through 10.15.6
  3. Check if running macOS Big Sur (11.x)
    If the version from step 1 begins with 11, confirm it is 11.0, 11.1, 11.2, or 11.3
    Affected if The system is running macOS Big Sur 11.0 through 11.3.x (any version below 11.4)
  4. Verify Security Update 2021-003 on Catalina
    Run: system_profiler SPSoftwareDataType | grep 'Security Update'
    Affected if The output does not show 'Security Update 2021-003' or later for macOS 10.15.7 systems

You are affected if running macOS 10.15 through 10.15.6, or macOS 10.15.7 without Security Update 2021-003, or macOS 11.0 through 11.3.x without the 11.4 update.

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 11.4 or later
Fixed in 11.4
Interim mitigation

Apply the vendor-supplied security updates: macOS Big Sur 11.4 or later, or Security Update 2021-003 for macOS Catalina. Alternatively, upgrade to the latest supported macOS version to receive current security patches.

Recommended fix High confidence

macOS Big Sur 11.4 or Security Update 2021-003 for Catalina (10.15.7)

  1. Back up your Mac using Time Machine before initiating any system update
  2. Open System Preferences and click on Software Update to check for available updates
  3. For macOS Catalina (10.15.x) systems: Install Security Update 2021-003 Catalina when it appears in Software Update
  4. For macOS Big Sur (11.0-11.3) systems: Install macOS Big Sur 11.4 when it appears in Software Update
  5. After installation completes, restart your Mac when prompted
  6. Verify the update was successful by going to System Preferences > About and confirming the version shows 10.15.7 with Security Update 2021-003 or macOS 11.4
Caveat Standard macOS upgrade considerations apply: ensure critical applications are compatible, verify backup is complete before proceeding, and ensure sufficient battery or power connection during update

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

Fix this in Mac Os X Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
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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-2021-30688 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