Iphone OsOperating system · Apple

CVE-2019-8631

HIGH · 7.5 CVSS v3.1 Published 2020-10-27
Fix available
A fix is available. Upgrade to 10.14.5 / 12.3 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
A logic issue was addressed with improved state management. This issue is fixed in macOS Mojave 10.14.5, Security Update 2019-003 High Sierra, Security Update 2019-003 Sierra, iOS 12.3, tvOS 12.3. Users removed from an iMessage conversation may still be able to alter state.

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 · moderate confidence

A logic flaw in iMessage allowed users who were removed from a conversation to still modify conversation state due to improper state management. This authorization bypass permitted former participants to alter iMessage thread state after removal.

MitigationApply the relevant Apple security updates: macOS Mojave 10.14.5, Security Update 2019-003 for High Sierra/Sierra, iOS 12.3, or tvOS 12.3 depending on affected platform.

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:< 12.3
Mac Os XOperating system
Affected:< 10.14.5
TvosOperating system
Affected:< 12.3

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
High
Availability
None

CVSS:3.1/AV:N/AC:L/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 checks

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

  1. Check iOS version on iPhone/iPad
    Go to Settings > General > About > Version, or run 'sw_vers' in terminal, or check via Apple Configurator or MDM
    Affected if iOS version is below 12.3 and iMessage is enabled
  2. Check macOS version on Mac
    Go to Apple menu > About This Mac > Version, or run 'sw_vers' in Terminal
    Affected if macOS version is below 10.14.5 and iMessage is signed in
  3. Check tvOS version on Apple TV
    Go to Settings > General > About > Version, or check via Xcode or device management tool
    Affected if tvOS version is below 12.3 and iMessage is configured (via Messages in iCloud)
  4. Verify iMessage is active
    On iOS: Open Messages app and check for existing conversations. On macOS: Open Messages app and verify account is signed in. On tvOS: Check if Messages in iCloud is enabled in Settings > Accounts.
    Affected if iMessage is enabled/active on the device

A user is affected if they are running a vulnerable OS version (iOS < 12.3, macOS < 10.14.5, or tvOS < 12.3) AND iMessage is enabled, allowing removed participants to potentially modify conversation state.

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 10.14.5 / 12.3 or later
Fixed in 10.14.512.3
Interim mitigation

Apply the relevant Apple security updates: macOS Mojave 10.14.5, Security Update 2019-003 for High Sierra/Sierra, iOS 12.3, or tvOS 12.3 depending on affected platform.

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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Scan for this in your stack

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dbcve dependency scanner

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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-2019-8631 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