CVE-2020-27917
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 use after free issue was addressed with improved memory management. This issue is fixed in macOS Big Sur 11.0.1, watchOS 7.1, iOS 14.2 and iPadOS 14.2, iCloud for Windows 11.5, tvOS 14.2, iTunes 12.11 for Windows. Processing maliciously crafted web content may lead to 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 confidenceA use-after-free vulnerability in WebKit allows remote attackers to execute arbitrary code by tricking users into processing maliciously crafted web content. The vulnerability stems from improper memory management during web content processing.
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< 11.5< 12.11< 14.2< 14.2>= 11.0, < 11.0.1< 14.2< 7.1CVSS 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
- High
- Availability
- High
CVSS:3.1/AV:L/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 installed Apple productsCheck system for presence of iCloud, iTunes, iPadOS, iPhone OS, macOS, tvOS, or watchOSAffected if Any of these products are installed and the version falls within the affected ranges
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Check iCloud for Windows versionOpen iCloud and navigate to Settings or About to view the version number, or check the installed program version via Windows Programs and FeaturesAffected if Version is less than 11.5
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Check iTunes for Windows versionOpen iTunes and go to Help > About iTunes, or check via Windows Programs and FeaturesAffected if Version is less than 12.11
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Check iPadOS or iPhone iOS versionGo to Settings > General > About on the device to view the iOS/iPadOS versionAffected if Version is less than 14.2
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Check macOS versionGo to Apple menu > About This Mac to view the macOS version numberAffected if Version is 11.0 (Big Sur initial release)
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Verify WebKit usage contextDetermine if the device or software processes web content through WebKit-based applications (Safari, embedded browsers, web views)Affected if WebKit processes untrusted web content on a vulnerable version
The environment is affected if any of these Apple products are installed with versions below the fixed releases (iOS 14.2, iPadOS 14.2, macOS 11.0.1, watchOS 7.1, tvOS 14.2, iCloud 11.5, or iTunes 12.11) and the device processes web content.
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.
From vendor data7.111.0.111.5
Apply the vendor-supplied patches: iOS 14.2, iPadOS 14.2, macOS Big Sur 11.0.1, watchOS 7.1, tvOS 14.2, iCloud for Windows 11.5, or iTunes 12.11 for Windows. Until patched, avoid visiting untrusted websites.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-27917 — 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-2020-27917 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