SafariWeb browser · Apple
CVE-2018-4277
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 · uneditedIn iOS before 11.4.1, watchOS before 4.3.2, tvOS before 11.4.1, Safari before 11.1.1, macOS High Sierra before 10.13.6, a spoofing issue existed in the handling of URLs. This issue was addressed with improved input validation.
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 confidenceA URL spoofing vulnerability existed in iOS, watchOS, tvOS, Safari, and macOS High Sierra before the specified versions. The issue allowed attackers to potentially misrepresent URLs through improper input validation during URL handling, enabling phishing or social engineering attacks.
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
SafariWeb browser
< 11.1.1< 11.4.1< 10.13.6< 11.4.1< 4.3.2CVSS 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
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
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 your Apple device and operating systemDetermine whether you are using iOS (iPhone/iPad), watchOS (Apple Watch), tvOS (Apple TV), Safari browser, or macOS High Sierra. Each has a separate version to check.Affected if You are using any of these Apple products and the specific version falls below the fixed release for that product.
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Check iOS version on iPhone or iPadGo to Settings > General > About. Look for the 'Version' field showing the iOS build (e.g., 11.4).Affected if The version is earlier than 11.4.1 (or the build number is earlier than the 11.4.1 security content release).
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Check watchOS version on Apple WatchOpen the Watch app on paired iPhone, go to General > About, or check the Apple Watch itself in Settings > General > About.Affected if The version is earlier than 4.3.2.
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Check tvOS version on Apple TVGo to Settings > General > About > Version on the Apple TV device.Affected if The version is earlier than 11.4.1.
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Check Safari version on macOSOpen Safari, click Safari menu > About Safari. The version number displays next to Safari (e.g., 11.1).Affected if The Safari version is earlier than 11.1.1.
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Check macOS High Sierra versionClick Apple menu > About This Mac. The macOS version displays as 'macOS High Sierra' followed by a version number (e.g., 10.13.5).Affected if The macOS version is earlier than 10.13.6.
You are affected if any Apple product (iOS, watchOS, tvOS, Safari, or macOS High Sierra) installed on your device or computer has a version number lower than the corresponding fixed release: iOS 11.4.1, watchOS 4.3.2, tvOS 11.4.1, Safari 11.1.1, or macOS 10.13.6.
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 data4.3.210.13.611.1.1
Apply the vendor-provided updates: iOS 11.4.1 or later, watchOS 4.3.2 or later, tvOS 11.4.1 or later, Safari 11.1.1 or later, and macOS High Sierra 10.13.6 or later.
Fix this in Safari
Scoped from the published advisory
- Consultation1.0 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-2018-4277 — 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-2018-4277 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