CVE-2021-30799
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 · uneditedMultiple memory corruption issues were addressed with improved memory handling. This issue is fixed in iOS 14.7, macOS Big Sur 11.5, Security Update 2021-004 Catalina, Security Update 2021-005 Mojave. Processing maliciously crafted web content may lead to arbitrary code execution.
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 confidenceMemory corruption vulnerability in WebKit (Apple's web rendering engine) allows arbitrary code execution when processing maliciously crafted web content. The vulnerability affects iOS and macOS devices and is exploitable without user interaction beyond visiting a malicious webpage.
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< 14.7>= 10.14, <= 10.14.6>= 10.15, < 10.15.7= 10.14.6= 10.15.6= 10.15.7>= 11.0, < 11.5CVSS 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
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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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Identify the operating systemDetermine if the device is running iOS (iPhone/iPad) or macOS (Mac computer)Affected if Device runs iOS or macOS and uses WebKit-based browsing
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Check iOS version on iPhone or iPadOpen Settings > General > About and note the version number (e.g., 14.6)Affected if iOS version is lower than 14.7 (e.g., 14.6, 14.5, etc.)
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Check macOS version on MacClick Apple menu > About This Mac or run 'sw_vers' in TerminalAffected if macOS version falls within these ranges: 10.14.x (any version), 10.15.x (any version), or 11.0 to 11.4.x (any version before 11.5)
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Verify WebKit is in useConfirm Safari or any third-party browser (Chrome, Firefox, etc.) or app using WebView is installed and enabled for web browsingAffected if WebKit-based browser or web-viewing app is present and used
A device is affected if it runs iOS before 14.7, or macOS versions 10.14.x, 10.15.x, or 11.0-11.4.x, and has WebKit-based browsing capability enabled.
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 · scoped10.15.711.514.7
Apply the vendor-supplied security updates: iOS 14.7, macOS Big Sur 11.5, Security Update 2021-004 Catalina, or Security Update 2021-005 Mojave depending on platform. Until patched, avoid browsing untrusted websites.
iOS 14.7+, macOS Big Sur 11.5+, Security Update 2021-004 Catalina, or Security Update 2021-005 Mojave depending on your OS version
- For iOS devices: Upgrade to iOS 14.7 or later by going to Settings > General > Software Update
- For macOS Big Sur (11.x) users: Upgrade to macOS Big Sur 11.5 or later via System Preferences > Software Update
- For macOS Catalina (10.15.x) users: Install Security Update 2021-004 Catalina via System Preferences > Software Update
- For macOS Mojave (10.14.x) users: Install Security Update 2021-005 Mojave via System Preferences > Software Update
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation6.0 h
- Testing4.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,512.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-30799 — 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-2021-30799 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