CVE-2018-4086
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 · uneditedAn issue was discovered in certain Apple products. iOS before 11.2.5 is affected. macOS before 10.13.3 is affected. tvOS before 11.2.5 is affected. watchOS before 4.2.2 is affected. The issue involves the "Security" component. It allows remote attackers to spoof certificate validation via crafted name constraints.
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 certificate validation bypass vulnerability in Apple's Security framework where crafted X.509 certificates with malicious name constraints can bypass validation checks, potentially enabling man-in-the-middle attacks by spoofing legitimate certificate identities.
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< 11.2.5< 11.2.5< 10.13.3< 4.2.2CVSS 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
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
CVSS:3.0/AV:N/AC:H/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 the installed Apple operating systemOn the device, go to Settings > General > About to find the version number. On macOS, use Apple menu > About This Mac. On Apple TV, go to Settings > General > About. On Apple Watch, use the Watch app on iPhone > General > About.Affected if the device runs any Apple OS (iOS, macOS, tvOS, watchOS)
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Determine if iOS version is affectedCheck the iOS version number displayed in Settings > General > About (for iPhone or iPad).Affected if the iOS version is below 11.2.5
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Determine if macOS version is affectedCheck the macOS version number displayed in About This Mac.Affected if the macOS version is below 10.13.3
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Determine if tvOS version is affectedCheck the tvOS version number displayed in Settings > General > About on Apple TV.Affected if the tvOS version is below 11.2.5
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Determine if watchOS version is affectedCheck the watchOS version using the Watch app on paired iPhone: General > About.Affected if the watchOS version is below 4.2.2
The environment is affected if any Apple device runs an OS version lower than the fixed release (iOS 11.2.5, macOS 10.13.3, tvOS 11.2.5, or watchOS 4.2.2), since the certificate validation bypass exists only in those earlier versions.
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 data4.2.210.13.311.2.5
Apply vendor-provided updates: iOS 11.2.5+, macOS 10.13.3+, tvOS 11.2.5+, and watchOS 4.2.2+ contain the fix for this certificate spoofing issue.
- Consultation8.0 h
- Implementation12.0 h
- Testing6.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-4086 — 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-2018-4086 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
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