CVE-2021-30716
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 logic issue was addressed with improved state management. This issue is fixed in macOS Big Sur 11.4, Security Update 2021-003 Catalina, Security Update 2021-004 Mojave. An attacker in a privileged network position may be able to perform denial of service.
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 logic flaw in macOS state management that allows an attacker with a privileged network position (e.g., man-in-the-middle) to cause a denial of service by manipulating network state 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>= 10.14, <= 10.14.5>= 10.15, <= 10.15.6= 10.14.6= 10.15.7>= 11.0, < 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
- Network
- Complexity
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/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 macOS versionOpen Terminal and run: sw_vers -productVersionAffected if Version is 10.14.x (through 10.14.5 or exactly 10.14.6), 10.15.x (through 10.15.6 or exactly 10.15.7), or 11.0-11.3 (anything less than 11.4)
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Verify network service statusCheck if active network services exist by running: networksetup -listallnetworkservicesAffected if Any network service (Wi-Fi, Ethernet, etc.) is enabled and active on the system
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Confirm network connectivity stateRun: ifconfig or networksetup -getcurrentlocation to see active network interfacesAffected if The system has an active network interface configured and connected, as the flaw manipulates network state handling
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Identify specific macOS buildRun: sw_vers -buildVersion to get the exact build numberAffected if Build number corresponds to an unpatched release (for 10.14.6 this would be 18G84, for 10.15.7 this would be 19H114, for 11.0-11.3 builds prior to 20F71)
The system is affected if it runs any macOS version in the 10.14.x, 10.15.x, or 11.0-11.3 range AND has active network connectivity, since exploitation requires a privileged network position to manipulate network state handling.
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 appropriate Apple security update: macOS Big Sur 11.4, Security Update 2021-003 for Catalina, or Security Update 2021-004 for Mojave.
macOS Big Sur 11.4 (for macOS 11.0-11.3 users); Security Update 2021-003 Catalina (for macOS 10.15.x); Security Update 2021-004 Mojave (for macOS 10.14.x)
- For macOS Mojave (10.14.x): Open System Preferences > Software Update and install Security Update 2021-004 Mojave, or manually download from Apple Support downloads
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation1.0 h
- Implementation1.0 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-2021-30716 — 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-2021-30716 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