dbcve.org
Iphone OsOperating system · Apple

CVE-2018-4140

HIGH · 7.5 CVSS v3.0 Published 2018-04-03
Fix available
A fix is available. Upgrade to 11.3 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

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 11.3 is affected. The issue involves the "Telephony" component. It allows remote attackers to cause a denial of service (NULL pointer dereference and reboot) via a Class 0 SMS message.

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

The Telephony component in iOS before 11.3 contains a NULL pointer dereference vulnerability that can be triggered by receiving a specially crafted Class 0 SMS message. Class 0 SMS messages are immediate-display messages that appear on screen without being stored. When processed, the malformed message causes a NULL pointer dereference resulting in kernel panic and device reboot.

MitigationUpgrade iOS to version 11.3 or later to patch the vulnerability. Users should avoid opening SMS messages from untrusted sources as an interim precaution.

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
Iphone OsOperating system
Affected:< 11.3

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
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 iOS version installed on the device
    Go to Settings > General > About > Version, or use Finder/iTunes to check the iOS version, or run idevicesyslog or similar tool to retrieve system version
    Affected if The installed iOS version is any build before 11.3 (for example, 11.2.6, 11.2.5, 11.2.2, 11.2.1, 11.2, 11.1.2, etc.)
  2. Confirm device is an iPhone capable of SMS
    Verify the device model is an iPhone (not iPad or iPod touch) by checking Settings > General > About > Model Name
    Affected if The device is an iPhone model that supports SMS messaging via the Telephony component
  3. Verify Telephony component is active
    Confirm the device has cellular service and can receive SMS messages - check for carrier signal in status bar and verify cellular plan is active
    Affected if The device has cellular service enabled and the Telephony component is processing SMS traffic

A device is affected if it is an iPhone running any iOS version prior to 11.3 with cellular service active, as the NULL pointer dereference triggers when processing a malformed Class 0 SMS message.

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 11.3 or later
Fixed in 11.3
Interim mitigation

Upgrade iOS to version 11.3 or later to patch the vulnerability. Users should avoid opening SMS messages from untrusted sources as an interim precaution.

Fix this in Iphone Os Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing1.0 h
  • Review / QA1.0 h
5.0 hours of engineering $890
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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-2018-4140 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