CVE-2021-30879
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 · uneditedAn out-of-bounds read was addressed with improved bounds checking. This issue is fixed in macOS Monterey 12.0.1, Security Update 2021-007 Catalina, macOS Big Sur 11.6.1. Processing a maliciously crafted AppleScript binary may result in unexpected application termination or disclosure of process memory.
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 confidenceCVE-2021-30879 is an out-of-bounds read vulnerability in macOS AppleScript binary parsing. The flaw lacked proper bounds checking, allowing a maliciously crafted AppleScript binary to trigger memory reads outside allocated buffers, leading to application crashes or sensitive process memory disclosure.
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>= 10.15, <= 10.15.6= 10.15.7>= 11.0, < 11.6.1>= 12.0, < 12.0.1CVSS 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
- High
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/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 checksWork through these to decide whether this CVE applies to you.
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Check your macOS versionGo to Apple menu > About This Mac, or run 'sw_vers' in TerminalAffected if The version shown is 10.15.0 through 10.15.6, 10.15.7, 11.0 through 11.6.0, or 12.0
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Identify the OS build number (optional)Run 'uname -a' or check System Information > Software > VersionAffected if Running a build from the affected version ranges before the security patches
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Determine if AppleScript is in useCheck for any automation scripts or third-party apps that process AppleScript binaries (.scpt files) from external sourcesAffected if Your system processes AppleScript binaries from untrusted sources while running an affected macOS version
You are affected if your macOS version falls within 10.15.0-10.15.7, 11.0-11.6.0, or 12.0, and you process AppleScript binaries from untrusted sources.
Generated from the published advisory. Verify against your own configuration.
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 · scoped11.6.112.0.1
Apply the relevant macOS security update (Security Update 2021-007 for Catalina, macOS Big Sur 11.6.1, or macOS Monterey 12.0.1) and avoid processing untrusted AppleScript binaries from unknown sources.
macOS Catalina: Security Update 2021-007 | macOS Big Sur: 11.6.1 | macOS Monterey: 12.0.1
- Back up your Mac using Time Machine before applying any system updates
- For macOS Catalina (10.15.7): Install Security Update 2021-007 via System Preferences > Software Update
- For macOS Big Sur (11.0-11.6): Update to macOS Big Sur 11.6.1 or later via System Preferences > Software Update
- For macOS Monterey (12.0): Update to macOS 12.0.1 or later via System Preferences > Software Update
- After updating, verify the security update was applied by checking System Preferences > About > System Report > Software Update
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-30879 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-30879 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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
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