CVE-2021-30827
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 permissions issue existed. This issue was addressed with improved permission validation. This issue is fixed in Security Update 2021-005 Catalina, macOS Big Sur 11.6. A local attacker may be able to elevate their 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 · high confidenceThis is a local privilege escalation vulnerability in macOS Catalina and Big Sur 11.6 stemming from improper permission validation. A local authenticated attacker could exploit this to gain elevated (root) privileges on the affected system. The fix involves applying Apple's Security Update 2021-005 for Catalina or updating to macOS Big Sur 11.6 or later which includes improved permission validation.
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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/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.
-
Check the installed macOS versionOpen Terminal and run: sw_vers -productVersionAffected if The version output is 10.15.7 or earlier, or falls between 11.0 and 11.5.x (including 11.5, 11.5.1, etc.)
-
Confirm the macOS release nameRun: sw_vers -productVersionExtra in Terminal (if available) or check System Preferences > About to see if it shows Catalina or Big SurAffected if The system is running macOS Catalina (10.15.x) or Big Sur 11.0-11.5.x
-
Verify Security Update status for CatalinaFor macOS 10.15.x systems, run: defaults read /Library/Preferences/com.apple.SoftwareUpdate.plist LastSuccessfulDate 2>/dev/null or check System Preferences > Software UpdateAffected if No security update dated after August 2021 is present, or the system remains at 10.15.7 without Security Update 2021-005 applied
-
Verify Big Sur update statusFor macOS 11.x systems, run: sw_vers -productVersion and confirm the version is 11.6 or laterAffected if The system is running any version of Big Sur prior to 11.6
A system is affected if it runs macOS Catalina 10.15 through 10.15.7 or macOS Big Sur 11.0 through 11.5.x without the corresponding security updates applied.
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 the appropriate security update: Security Update 2021-005 for macOS Catalina, or update to macOS Big Sur 11.6 or later. Verify the update was successfully applied and monitor for any post-update anomalies.
Security Update 2021-005 Catalina for 10.15.x; macOS Big Sur 11.6 for 11.x
- For macOS X 10.15.x (Catalina) users: Apply Security Update 2021-005 Catalina via System Preferences > Software Update, or upgrade to a later macOS version if supported
- For macOS 11.x (Big Sur) users: Upgrade to macOS Big Sur 11.6 or later via System Preferences > Software Update
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation1.0 h
- Implementation2.0 h
- Testing1.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,424.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-30827 — 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-2021-30827 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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