SafariWeb browser · Apple
CVE-2016-4763
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 · uneditedWKWebView in WebKit in Apple iOS before 10, iTunes before 12.5.1 on Windows, and Safari before 10 does not properly verify X.509 certificates from HTTPS servers, which allows man-in-the-middle attackers to spoof servers and obtain sensitive information via a crafted certificate.
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 confidenceWKWebView in WebKit fails to properly verify X.509 certificates from HTTPS servers, allowing man-in-the-middle attackers to intercept encrypted traffic by presenting crafted certificates.
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
<= 9.1.3<= 12.4.3<= 9.3.5CVSS 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
- High
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- None
CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:H/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 which Apple product to checkDetermine if you are using Safari (desktop browser), iTunes (Windows media player), or iOS (iPhone/iPad). The CVE affects all three products.Affected if Using any of the affected products (Safari, iTunes, or iOS)
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Check Safari versionOn macOS: Open Safari, go to Safari menu > About Safari. On Windows: Open iTunes, go to Help > About iTunes (iTunes includes Safari). Compare the version number to 9.1.3.Affected if Safari version is 9.1.3 or earlier, or iTunes version is 12.4.3 or earlier on Windows
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Check iTunes version on WindowsOpen iTunes, go to Help > About iTunes. The version number displayed is the installed version.Affected if iTunes version is 12.4.3 or earlier on Windows
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Check iOS version on iPhone or iPadOn the device, go to Settings > General > About. The version number displayed is the installed iOS version.Affected if iOS version is 9.3.5 or earlier
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Verify WKWebView is in useWKWebView is the modern WebKit web view component used by apps for displaying web content. It is included in Safari, iTunes (Windows), and iOS. No separate configuration check is needed; the vulnerable component is present in affected versions.Affected if The product version is within the affected range, meaning the vulnerable WKWebView certificate verification code is present
You are affected if you are running any of these vulnerable versions: Safari 9.1.3 or earlier, iTunes 12.4.3 or earlier on Windows, or iOS 9.3.5 or earlier on iPhone/iPad, because they all contain the flawed WKWebView certificate verification.
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 dataUpdate affected Apple products (iOS to version 10 or later, Safari to version 10 or later, iTunes to 12.5.1 or later on Windows) to obtain the patched WebKit component.
Fix this in Safari
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,880.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2016-4763 — 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-2016-4763 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