CVE-2021-30719
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 local user may be able to cause unexpected system termination or read kernel memory. This issue is fixed in macOS Big Sur 11.4, Security Update 2021-003 Catalina. An out-of-bounds read issue was addressed by removing the vulnerable 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 · high confidenceCVE-2021-30719 is a local privilege escalation and information disclosure vulnerability in the macOS kernel (XNU). A local unprivileged user can exploit an out-of-bounds read vulnerability to either read arbitrary kernel memory or cause a kernel panic (system termination). The fix involved removing the vulnerable code path entirely rather than patching it.
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, < 11.4CVSS 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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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 installed macOS versionRun `sw_vers -productVersion` in Terminal to get the exact macOS version numberAffected if The version is 10.15.x (any version from 10.15 through 10.15.7) or 11.0 through 11.3.x (any version from 11.0 up to but not including 11.4)
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Verify macOS 10.15.7 patch statusFor macOS 10.15.7 specifically, run `defaults read /Library/Preferences/com.apple.SoftwareUpdate.plist LastRecommendedSecurityUpdates` or check if Security Update 2021-003 appears in System Preferences > Software UpdateAffected if Running macOS 10.15.7 without Security Update 2021-003 installed
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Confirm kernel version as secondary checkRun `uname -r` to get the kernel version, or check `/System/Library/CoreServices/SystemVersion.plist` for the build numberAffected if The kernel version or build number corresponds to an unpatched release (build numbers before the security update)
You are affected if your macOS version is 10.15.x without Security Update 2021-003, or 11.0-11.3.x without having updated to 11.4 or later.
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 later, or Security Update 2021-003 for macOS Catalina. This is a straightforward OS patch deployment that eliminates the vulnerable code path.
macOS Big Sur 11.4 or later / Security Update 2021-003 Catalina
- Back up your Mac using Time Machine or another backup solution before applying updates
- For macOS Big Sur (11.0-11.3): Go to System Preferences > Software Update and install macOS Big Sur 11.4 or later
- For macOS Catalina (10.15.7 and earlier): Go to System Preferences > Software Update and install Security Update 2021-003 Catalina
- After updating, verify the installation by checking System Preferences > Software Update to confirm no additional updates are available
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation2.0 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 $1,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-30719 — 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-2021-30719 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