CVE-2021-30731
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 · uneditedThis issue was addressed with improved checks. This issue is fixed in macOS Big Sur 11.4, Security Update 2021-004 Catalina. An unprivileged application may be able to capture USB devices.
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 confidenceAn unprivileged application can capture USB devices due to insufficient authorization checks in macOS. The vulnerability allows a non-admin user to access USB devices they should not have permission to access, representing a local privilege escalation issue in USB device handling.
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>= 11.0.1, < 11.4CVSS 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
- None
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/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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Identify the installed macOS versionRun 'sw_vers -productVersion' in Terminal to get the exact version number (e.g., 10.15.7, 11.3.1, 11.4)Affected if The version falls within 10.15 to 10.15.6 inclusive, equals 10.15.7, or is between 11.0.1 and 11.3.x inclusive (anything less than 11.4)
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Verify the specific macOS release nameRun 'sw_vers -productName' to confirm whether the system is running macOS Catalina (10.15.x) or macOS Big Sur (11.x)Affected if The system is running Catalina 10.15.x or Big Sur 11.0.1 through 11.3.x
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Confirm the minor version for CatalinaIf on macOS 10.15.x, run 'sw_vers -productVersion' and note the full version string (10.15.7 is the only patched version in the 10.15 line)Affected if The version is 10.15.7 or earlier (any version from 10.15 through 10.15.7 is affected if not patched)
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Confirm the minor version for Big SurIf on macOS 11.x, run 'sw_vers -productVersion' to get the exact build (11.4 and later contain the fix)Affected if The version is 11.0.1, 11.1, 11.2, 11.3, or 11.3.1 (any 11.x version before 11.4)
A user is affected if their macOS version is 10.15.x (any version from 10.15 through 10.15.7) or 11.0.1 through 11.3.x, as these versions contain the insufficient USB authorization check 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 · scoped11.4
Apply the vendor-supplied patches: macOS Big Sur 11.4 or Security Update 2021-004 for Catalina. This is an OS-level fix requiring standard patch deployment.
macOS Big Sur 11.4 or later; Security Update 2021-004 for Catalina
- For macOS Big Sur (11.x) users: Update to macOS Big Sur 11.4 or later via Apple menu > System Preferences > Software Update
- For macOS Catalina (10.15.x) users: Apply Security Update 2021-004 via Apple menu > System Preferences > Software Update
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation1.0 h
- Implementation1.0 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-2021-30731 — 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-2021-30731 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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