dbcve.org
IpadosOperating system · Apple

CVE-2021-30831

MEDIUM · 5.5 CVSS v3.1 Published 2021-10-28
Fix available
A fix is available. Upgrade to 8.0 / 12.0.1 or later.
See remediation →
58/100
Remediation priority · Elevated
No privileges

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 out-of-bounds read was addressed with improved input validation. This issue is fixed in tvOS 15, watchOS 8, iOS 15 and iPadOS 15. Processing a maliciously crafted font may result in the disclosure of process memory.

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

An out-of-bounds read vulnerability in Apple's font processing subsystem (CoreText/CoreGraphics) allows a maliciously crafted font file to be processed, causing the application to read memory beyond allocated boundaries. This leads to disclosure of process memory to an attacker.

MitigationApply vendor patches by updating affected devices to iOS 15+, iPadOS 15+, watchOS 8+, or tvOS 15+. For enterprise fleets, deploy OS updates through MDM or patch management tooling.

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
IpadosOperating system
Affected:< 15.0
Iphone OsOperating system
Affected:< 15.0
macOSOperating system
Affected:< 12.0.1
TvosOperating system
Affected:< 15.0
WatchosOperating system
Affected:< 8.0

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
Local
Complexity
Low
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/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. Identify your Apple device and operating system
    Determine whether the device runs iOS (iPhone), iPadOS (iPad), macOS (Mac), watchOS (Apple Watch), or tvOS (Apple TV). Check System Settings or About This Mac for the exact OS name and version number.
    Affected if Device runs any of iOS, iPadOS, watchOS, or tvOS versions prior to 15.0, or macOS prior to 12.0.1
  2. Verify iOS or iPadOS version
    On iPhone or iPad, go to Settings > General > About. Note the Version number. Compare it to 15.0 - the fix is 15.0 and later.
    Affected if Version is below 15.0 (for example, 14.7.1, 14.6, etc.)
  3. Verify macOS version
    On Mac, go to Apple menu > About This Mac. Note the macOS version. Compare it to 12.0.1 - the fix is 12.0.1 and later.
    Affected if Version is below 12.0.1 (for example, 12.0, 11.6, etc.)
  4. Verify watchOS version
    On Apple Watch, open the Settings app > General > About. Or check in the Watch app on iPhone under My Watch > General > About. Compare to 8.0 - the fix is 8.0 and later.
    Affected if Version is below 8.0 (for example, 7.6, 7.5, etc.)
  5. Verify tvOS version
    On Apple TV, go to Settings > General > About. Note the version. Compare to 15.0 - the fix is 15.0 and later.
    Affected if Version is below 15.0 (for example, 14.7, 14.6, etc.)

You are affected if your device runs any version below iOS 15.0, iPadOS 15.0, watchOS 8.0, tvOS 15.0, or macOS 12.0.1 AND you open or process a maliciously crafted font file.

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.

dbcve · scoped
Upgrade available Upgrade to 8.0 / 12.0.1 / 15.0 or later
Fixed in 8.012.0.115.0
Interim mitigation

Apply vendor patches by updating affected devices to iOS 15+, iPadOS 15+, watchOS 8+, or tvOS 15+. For enterprise fleets, deploy OS updates through MDM or patch management tooling.

Recommended fix High confidence

iOS 15+, iPadOS 15+, macOS 12.0.1+, tvOS 15+, watchOS 8+

  1. Upgrade iOS devices (iPhone and iPad) to iOS 15.0 or later
  2. Upgrade macOS devices to macOS 12.0.1 (Monterey) or later
  3. Upgrade Apple TV devices to tvOS 15.0 or later
  4. Upgrade Apple Watch devices to watchOS 8.0 or later
  5. After upgrading, verify the version in Settings > General > About on iOS devices, or System Preferences > About on macOS
Caveat Standard upgrade considerations apply: backup important data before upgrading, some legacy apps may not be compatible with newer OS versions

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Ipados Scoped from the published advisory
  • Consultation2.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
16.0 hours of engineering $2,800
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,480.

Scan for this in your stack

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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-2021-30831 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