CVE-2021-30717
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 memory corruption 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 execute arbitrary code.
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 confidenceMemory corruption vulnerability in macOS (affected versions: Catalina, Mojave, Big Sur pre-11.4) allowing arbitrary code execution via a privileged network position. The fix involves improved state management to prevent the memory corruption.
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
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:H/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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Determine your macOS versionRun 'sw_vers -productVersion' in Terminal or check System Preferences > About This Mac > VersionAffected if The displayed version falls within the affected ranges (10.14.x, 10.15.x, or 11.0-11.3.x)
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Identify the specific release numberRun 'sw_vers -productVersion' and note the full version string (e.g., 10.15.7, 11.3.1)Affected if Version is 10.14.6 or earlier, 10.15.7 or earlier, or 11.0-11.3.x (any version below 11.4)
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Confirm macOS lineageRun 'sw_vers -productVersion' and map the major version number: 10.14 = Mojave, 10.15 = Catalina, 11.x = Big SurAffected if Running Mojave (10.14.x), Catalina (10.15.x), or Big Sur versions prior to 11.4
You are affected if your macOS version is Mojave 10.14.6 or earlier, Catalina 10.15.7 or earlier, or Big Sur 11.0 to 11.3.x; the vulnerability is present in the OS itself and requires no specific configuration to be exploitable from a privileged network position.
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 macOS security update: Security Update 2021-003 for Catalina, Security Update 2021-004 for Mojave, or macOS Big Sur 11.4 or later.
macOS Big Sur 11.4+, Security Update 2021-003 Catalina, or Security Update 2021-004 Mojave
- Back up your Mac using Time Machine before applying any updates
- Check your current macOS version by clicking Apple menu > About This Mac
- For macOS Big Sur (11.0-11.3) users: Install macOS Big Sur 11.4 or later via System Preferences > Software Update
- For macOS Catalina (10.15) users: Apply Security Update 2021-003 via System Preferences > Software Update
- For macOS Mojave (10.14) users: Apply Security Update 2021-004 via System Preferences > Software Update
- Restart your Mac after the update installs to complete the patching process
- Verify the update was applied by checking System Preferences > Software Update for no remaining updates
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 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 $2,880.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-30717 — 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-2021-30717 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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