dbcve.org
Mac Os XOperating system · Apple

CVE-2021-30963

MEDIUM · 5.5 CVSS v3.1 Published 2021-08-24
Fix available
A fix is available. Upgrade to 11.6.2 or later.
See remediation →
58/100
Remediation priority · Elevated
No privileges

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 issue was addressed with improved memory handling. This issue is fixed in Security Update 2021-008 Catalina, macOS Big Sur 11.6.2. Parsing a maliciously crafted audio file may lead to disclosure of user information.

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 buffer overflow vulnerability exists in macOS audio parsing functionality. When parsing a maliciously crafted audio file, improper memory handling allows an attacker to read beyond allocated buffer boundaries, potentially exposing sensitive user information stored in memory.

MitigationApply Apple security updates (Security Update 2021-008 for Catalina, macOS Big Sur 11.6.2 or later). Users should avoid opening audio files from untrusted sources until systems are patched.

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

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
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/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 your macOS version
    Click the Apple menu > About This Mac. The version number is displayed under the macOS name. Alternatively, run 'sw_vers -productVersion' in Terminal.
    Affected if The version is 10.15.x (anywhere from 10.15 through 10.15.7) OR 11.0 through 11.6.1. Versions 10.15.8 and beyond, or 11.6.2 and beyond, are not affected.
  2. Verify the Core Audio component is present
    Core Audio is a built-in macOS framework. Confirm it exists by checking for /System/Library/Frameworks/CoreAudio.framework in Finder or running 'ls /System/Library/Frameworks/CoreAudio.framework' in Terminal.
    Affected if The framework exists and is used by any application that handles audio files on the system.
  3. Identify applications that process audio files
    Run 'ps aux | grep -i audio' in Terminal to list running processes related to audio. Also review your commonly used media applications (QuickTime, Music, GarageBand, Audacity, etc.).
    Affected if Any application that parses audio files is potentially using the vulnerable code path.
  4. Check for recently opened suspicious audio files
    Review your Downloads folder and recent documents for unknown or untrusted audio files (.mp3, .wav, .aac, .m4a, .aiff, .flac). Run 'ls -la ~/Downloads' in Terminal to list recent files.
    Affected if A maliciously crafted audio file was opened on the system, triggering the vulnerability.
  5. Look for signs of anomalous process behavior
    Open Activity Monitor and check for processes with unusually high memory usage or unexpected network connections. In Terminal, run 'log show --predicate 'process == "coreaudiod"' --last 24h' to review Core Audio daemon logs for errors.
    Affected if The coreaudiod process shows unexpected behavior or the logs contain memory-related errors during audio file processing.

You are affected if your system runs macOS 10.15.x through 10.15.7 or macOS 11.0 through 11.6.1 and you have opened audio files from untrusted sources, as the buffer overflow occurs during audio parsing.

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 11.6.2 or later
Fixed in 11.6.2
Interim mitigation

Apply Apple security updates (Security Update 2021-008 for Catalina, macOS Big Sur 11.6.2 or later). Users should avoid opening audio files from untrusted sources until systems are patched.

Recommended fix High confidence

macOS 10.15.7 with Security Update 2021-008, or macOS Big Sur 11.6.2

  1. Check current macOS version by clicking Apple menu > About This Mac
  2. If running macOS 10.15.x (Catalina), apply Security Update 2021-008: Go to System Preferences > Software Update and install the update, or download from Apple support downloads
  3. If running macOS 11.0-11.6.1 (Big Sur), upgrade to macOS Big Sur 11.6.2: Go to System Preferences > Software Update and install the update, or download from Apple support downloads
  4. After updating, verify the installation was successful and the system is running the patched version
Caveat Security updates typically have minimal risk; they address this vulnerability without major system changes

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
  • Review / QA1.0 h
3.0 hours of engineering $750
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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-2021-30963 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