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SafariWeb browser · Apple

CVE-2018-4190

HIGH · 8.8 CVSS v3.0 Published 2018-06-08
Fix available
A fix is available. Upgrade to 7.5 / 11.1.1 or later.
See remediation →
95/100
Remediation priority · Urgent
Remotely reachable No privileges

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 · unedited
An issue was discovered in certain Apple products. iOS before 11.4 is affected. Safari before 11.1.1 is affected. iCloud before 7.5 on Windows is affected. iTunes before 12.7.5 on Windows is affected. tvOS before 11.4 is affected. The issue involves the "WebKit" component. It allows remote attackers to obtain sensitive credential information that is transmitted during a CSS mask-image fetch.

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 confidence

This is a WebKit vulnerability allowing remote attackers to intercept sensitive credentials transmitted during CSS mask-image fetches. The attack exploits how WebKit handles the CSS mask-image property, potentially causing the browser to send authentication credentials to malicious third-party servers when fetching mask images.

MitigationApply the vendor-supplied patches for the affected products (iOS 11.4+, Safari 11.1.1+, iCloud 7.5+, iTunes 12.7.5+, tvOS 11.4+) to fix the credential leakage in WebKit's CSS mask-image handling.

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
Affected:< 11.1.1
Ubuntu LinuxOperating system
Affected:= 16.04= 17.10= 18.04
Iphone OsOperating system
Affected:< 11.4
TvosOperating system
Affected:< 11.4
IcloudApplication
Affected:< 7.5
ItunesApplication
Affected:< 12.7.5

CVSS 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:3.0/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 checks

Work through these to decide whether this CVE applies to you.

  1. Check Safari version on macOS
    Open Safari, click Safari menu > About Safari, or run `defaults read /Applications/Safari.app/Contents/Info CFBundleShortVersionString` in Terminal
    Affected if Version is lower than 11.1.1
  2. Check iOS version on iPhone/iPad
    Go to Settings > General > About, or connect device to computer and check in Finder/iTunes
    Affected if Version is lower than 11.4
  3. Check tvOS version on Apple TV
    Go to Settings > General > About > Version, or check via Finder/iTunes when connected
    Affected if Version is lower than 11.4
  4. Check iTunes version on Windows or macOS
    Open iTunes > Help > About iTunes, or check installed version in Programs and Features
    Affected if Version is lower than 12.7.5
  5. Check iCloud for Windows version
    Open iCloud app > click the gear icon > About, or check in Programs and Features
    Affected if Version is lower than 7.5
  6. Check WebKitGTK+ version on Ubuntu Linux
    Run `dpkg -l libwebkit2gtk-4.0-37` or `apt show libwebkit2gtk-4.0-37` to identify the installed WebKit version
    Affected if Running Ubuntu 16.04, 17.10, or 18.04 with an unpatched WebKitGTK+ version (the specific version number depends on the distribution's patch state)

You are affected if any of Safari < 11.1.1, iOS < 11.4, tvOS < 11.4, iTunes < 12.7.5, iCloud < 7.5, or Ubuntu 16.04/17.10/18.04 with an unpatched WebKitGTK+ is in use, and the browser is used to load untrusted web pages that could exploit the CSS mask-image credential leakage.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Upgrade available Upgrade to 7.5 / 11.1.1 / 11.4 or later
Fixed in 7.511.1.111.4
Interim mitigation

Apply the vendor-supplied patches for the affected products (iOS 11.4+, Safari 11.1.1+, iCloud 7.5+, iTunes 12.7.5+, tvOS 11.4+) to fix the credential leakage in WebKit's CSS mask-image handling.

Fix this in Safari Scoped from the published advisory
  • Consultation4.0 h
  • Implementation16.0 h
  • Testing8.0 h
  • Review / QA4.0 h
32.0 hours of engineering $5,600
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2018-4190 in production — separate from our analysis above.

No notes yet

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What this is

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.

What belongs here
  • 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