CVE-2018-4131
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 11.3 is affected. macOS before 10.13.4 is affected. The issue involves the "WindowServer" component. It allows attackers to bypass the Secure Input Mode protection mechanism, and log keystrokes of arbitrary apps, via a crafted app that scans key states.
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 confidenceThis vulnerability in the WindowServer component of iOS and macOS allows a malicious crafted application to bypass the Secure Input Mode protection mechanism by scanning key states, enabling attackers to log keystrokes from arbitrary applications.
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< 11.3< 10.13.4CVSS 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:3.0/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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Check installed iOS versionOn the iOS device, go to Settings > General > About and note the Version number. Compare it to the affected range (anything below 11.3).Affected if The version displayed is less than 11.3 (e.g., 11.2.6, 11.2.5, etc.)
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Check installed macOS versionOn Mac, click the Apple menu > About This Mac. Note the macOS version number (such as 10.13.3, 10.13.2, etc.). Compare to the affected range (anything below 10.13.4).Affected if The macOS version is 10.13.3 or earlier.
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Verify WindowServer is runningOn macOS, open Activity Monitor, search for 'WindowServer', or run 'ps -ef | grep WindowServer' in Terminal. On iOS, this runs as the loginwindow process.Affected if WindowServer is active and the OS version is in the vulnerable range.
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Check for unauthorized keylogger activityOn macOS, run 'sudo log show --predicate 'process == "WindowServer"' --last 1h' to review recent WindowServer logs for unusual key state polling patterns or unexpected input monitoring attempts.Affected if Logs show repeated key state queries from untrusted processes while Secure Input Mode is active.
You are affected if your device runs iOS versions before 11.3 or macOS versions before 10.13.4, as these contain the vulnerable WindowServer component that can bypass Secure Input Mode.
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 data10.13.411.3
Upgrade affected devices to iOS 11.3 or later and macOS 10.13.4 or later to patch the WindowServer vulnerability.
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-4131 — 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-2018-4131 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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