CVE-2021-30655
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 application may be able to execute arbitrary code with system privileges. This issue is fixed in macOS Big Sur 11.3, Security Update 2021-002 Catalina. The issue was addressed with improved permissions logic.
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 confidenceThis is a privilege escalation vulnerability in macOS that allows an application to execute arbitrary code with system (root) privileges. The vulnerability resided in the permissions logic of the operating system and was addressed with improved permissions controls in the security updates.
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, <= 10.15.5= 10.15.6= 10.15.7>= 11.0, < 11.3CVSS 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
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/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.
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Check installed macOS versionRun 'sw_vers -productVersion' in Terminal to see the exact version number (e.g., 10.15.7, 11.2.1)Affected if The version is 10.15, 10.15.5, 10.15.6, 10.15.7, or any 11.0.x through 11.2.x release
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Confirm macOS build dateRun 'sw_vers -buildVersion' and note the build string; compare against Apple's security update release dates for your versionAffected if The build predates the Security Update 2021-002 (Catalina) or macOS 11.3 (Big Sur) release date
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List installed security updatesRun 'system_profiler SPSoftwareDataType' and look for 'Security Update' entries in the output, or check /Library/Receipts for installed update receiptsAffected if No Security Update 2021-002 (for 10.15.x) or no macOS 11.3 update (for 11.x) is listed as installed
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Verify patch status via softwareupdateRun 'softwareupdate -l' to list available updates; if security updates for this CVE still appear as pending, the system is vulnerableAffected if Any security update related to CVE-2021-30655 remains outstanding or uninstalled
The system is affected if it runs macOS Catalina 10.15.x or Big Sur 11.0-11.2 and has not received the specific security update (2021-002 for Catalina or 11.3 for Big Sur) that addresses this vulnerability.
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 · scoped11.3
Apply the vendor-supplied security updates: macOS Big Sur 11.3 or Security Update 2021-002 for Catalina. Prioritize systems based on exposure and criticality.
macOS Big Sur 11.3 or Security Update 2021-002 for Catalina
- Backup important data using Time Machine or another backup solution
- For macOS Catalina (10.15.x) users: Go to System Preferences > Software Update and install Security Update 2021-002 Catalina
- For macOS Big Sur (11.0-11.2) users: Go to System Preferences > Software Update and upgrade to macOS Big Sur 11.3
- After updating, verify the installation was successful by checking the macOS version in About This Mac
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
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,560.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-30655 — 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-2021-30655 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
- No spam, self-promotion, credentials, or personal data