CVE-2021-30913
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 · uneditedThe issue was addressed with improved permissions logic. This issue is fixed in macOS Monterey 12.0.1, macOS Big Sur 11.6.1. An unprivileged application may be able to edit NVRAM variables.
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 confidenceA permissions flaw in macOS Big Sur and Monterey allowed unprivileged applications to modify NVRAM (Non-Volatile RAM) variables, which typically store critical system configuration settings. The vulnerability was caused by insufficient access controls on NVRAM modification routines, potentially allowing a low-privilege attacker to alter boot parameters or other system settings.
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, < 10.15.7= 10.15.7>= 11.0, < 11.6.1= 12.0CVSS 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
- None
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/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 checksWork through these to decide whether this CVE applies to you.
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Check installed macOS versionRun `sw_vers -productVersion` in Terminal to get the exact version numberAffected if Version is 10.15.7, any 10.15.x version, any version from 11.0 through 11.6.0, or exactly 12.0
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Confirm macOS name and buildRun `uname -a` and compare against Apple security advisory for build numbersAffected if Running unpatched macOS Catalina (10.15.x), Big Sur 11.0-11.6.0, or Monterey 12.0
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Verify NVRAM write access (optional safe check)Use `nvram -p` to read current NVRAM variables, then attempt a test variable write with limited user account if possibleAffected if Unprivileged user account can successfully write arbitrary NVRAM variables
System is affected if running macOS 10.15.7, any 10.15.x, 11.0-11.6.0, or exactly 12.0 without the corresponding security updates (Big Sur 11.6.1+ or Monterey 12.0.1+).
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 · scoped10.15.711.6.1
Apply macOS security updates: upgrade to macOS Monterey 12.0.1 or later, or macOS Big Sur 11.6.1 or later. This is a patch-based remediation requiring OS updates rather than configuration changes.
macOS Big Sur 11.6.1 or macOS Monterey 12.0.1 (depending on which macOS major version is currently running)
- Check the current macOS version by clicking the Apple menu and selecting 'About This Mac'
- For macOS Big Sur 11.0-11.6.x users: Upgrade to macOS Big Sur 11.6.1 via System Preferences > Software Update
- For macOS Monterey 12.0 users: Upgrade to macOS Monterey 12.0.1 (or later) via System Preferences > Software Update
- For macOS Catalina 10.15.x users: Apple did not release a 10.15.7 fix for this CVE; upgrade to macOS Big Sur 11.6.1 or later is recommended
- After upgrading, verify the fix by confirming that unprivileged applications can no longer modify NVRAM variables
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation1.0 h
- Testing4.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-30913 — 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-2021-30913 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
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