CVE-2021-30830
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 · uneditedA memory corruption issue was addressed with improved memory handling. This issue is fixed in Security Update 2021-005 Catalina, macOS Big Sur 11.6. A malicious 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 confidenceA memory corruption vulnerability in the macOS kernel (likely in IOKit/IORegistry framework) allows a malicious local application to execute arbitrary code with kernel-level privileges, achieving local privilege escalation. This is a use-after-free or similar memory handling flaw in kernel-space code.
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, < 11.6CVSS 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
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/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 checksWork through these to decide whether this CVE applies to you.
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Check installed macOS versionRun `sw_vers -productVersion` in Terminal or view System Preferences > AboutAffected if Version matches 10.15, 10.15.1, 10.15.2, 10.15.3, 10.15.4, 10.15.5, 10.15.6, 10.15.7, 11.0, 11.1, 11.2, 11.3, 11.4, or 11.5
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Confirm macOS release nameRun `sw_vers -productVersion` and note whether the major version is 10.x (Catalina) or 11.x (Big Sur)Affected if Running macOS Catalina 10.15.x or macOS Big Sur 11.0-11.5
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Verify patch statusCheck System Preferences > Software Update for available security updates, or run `system_profiler SPSoftwareDataType` to view installed updatesAffected if Security Update 2021-005 for Catalina is not installed, or macOS is not updated to 11.6 or later
A system is affected if it runs macOS Catalina 10.15.x (any subversion) or macOS Big Sur 11.0 through 11.5 and lacks the corresponding security patch.
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
Apply Security Update 2021-005 for macOS Catalina or update to macOS Big Sur 11.6 or later to patch the kernel memory corruption. Alternatively, restrict execution of untrusted applications via Gatekeeper and disable or limit local user privileges.
macOS 10.15.7 with Security Update 2021-005 Catalina, or macOS Big Sur 11.6
- Check current macOS version by clicking Apple menu > About This Mac
- Back up important data using Time Machine or another backup method
- For macOS 10.15.x (Catalina): Install Security Update 2021-005 by opening System Preferences > Software Update, or download from Apple Support downloads
- For macOS 11.x (Big Sur): Upgrade to macOS Big Sur 11.6 by opening System Preferences > Software Update, or download from Apple Support downloads
- Restart the system after the update completes
- Verify the update was applied by checking About This Mac > System Report > Software > Installed Security Updates
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation2.0 h
- Testing1.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-30830 — 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-2021-30830 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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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.
- 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