dbcve.org
Mac Os XOperating system · Apple

CVE-2021-30783

MEDIUM · 6.5 CVSS v3.1 Published 2021-09-08
Fix available
A fix is available. Upgrade to 11.5 or later.
See remediation →
67/100
Remediation priority · Elevated
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
An access issue was addressed with improved access restrictions. This issue is fixed in macOS Big Sur 11.5, Security Update 2021-004 Catalina, Security Update 2021-005 Mojave. A sandboxed process may be able to circumvent sandbox restrictions.

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

This is a sandbox bypass vulnerability in macOS where a sandboxed process could potentially circumvent sandbox restrictions due to an access control issue. The vulnerability was addressed with improved access restrictions in the specified macOS versions.

MitigationApply the relevant security update: macOS Big Sur 11.5, Security Update 2021-004 for Catalina, or Security Update 2021-005 for Mojave, depending on the macOS version in use.

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, <= 10.14.5>= 10.15, <= 10.15.6= 10.14.6= 10.15.7
macOSOperating system
Affected:>= 11.0, < 11.5

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
None
Integrity
High
Availability
None

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N

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 macOS version
    Run 'sw_vers -productVersion' in Terminal to get the exact macOS version number
    Affected if The version falls within 10.14 to 10.14.6, 10.15 to 10.15.7, or 11.0 to 11.4
  2. Identify macOS release name
    Run 'sw_vers -productName' to determine if the system is Mojave, Catalina, or Big Sur
    Affected if The release is Mojave (10.14.x), Catalina (10.15.x), or Big Sur (11.x)
  3. Verify security update installation
    Check System Preferences > Security & Privacy > General for recent security updates, or run 'defaults read /Library/Preferences/com.apple.SoftwareUpdate.plist LastSuccessfulDate'
    Affected if No security update installed after July 2021 (or the specific update 2021-004/2021-005/11.5 not present)
  4. Confirm sandbox is in use
    Check if any applications or processes are running with sandbox entitlements by reviewing sandbox profiles in /System/Library/Sandbox/Profiles/ or using 'ps aux | grep -i sandbox'
    Affected if Sandboxed applications are present on the system

The system is affected if it runs macOS Mojave 10.14.x, Catalina 10.15.x, or Big Sur 11.0-11.4 and has not installed the July 2021 security updates (2021-004/2021-005 or 11.5).

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 11.5 or later
Fixed in 11.5
Interim mitigation

Apply the relevant security update: macOS Big Sur 11.5, Security Update 2021-004 for Catalina, or Security Update 2021-005 for Mojave, depending on the macOS version in use.

Recommended fix High confidence

macOS Big Sur 11.5+ or apply Security Update 2021-004 (Catalina) / Security Update 2021-005 (Mojave)

  1. Check the current macOS version by clicking Apple menu > About This Mac
  2. For macOS Big Sur (11.0-11.4): Open System Preferences > Software Update to install macOS Big Sur 11.5 or later
  3. For macOS Catalina (10.15): Open System Preferences > Software Update to install Security Update 2021-004 Catalina
  4. For macOS Mojave (10.14.6, 10.14.5 and earlier): Open System Preferences > Software Update to install Security Update 2021-005 Mojave
  5. Verify the update was installed successfully by checking the Security Update version in System Preferences > Software Update
Caveat Security updates are low-risk cumulative patches; installing them is recommended without expected breaking changes

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-2021-30783 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