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Iphone OsOperating system · Apple

CVE-2021-30780

HIGH · 7.8 CVSS v3.1 Published 2021-09-08
Fix available
A fix is available. Upgrade to 7.6 / 11.5 or later.
See remediation →
81/100
Remediation priority · High
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 write issue was addressed with improved bounds checking. This issue is fixed in iOS 14.7, macOS Big Sur 11.5, watchOS 7.6, tvOS 14.7, Security Update 2021-005 Mojave, Security Update 2021-004 Catalina. A malicious application may be able to gain root privileges.

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 write vulnerability in Apple's core operating systems (iOS, macOS, watchOS, tvOS) allows a malicious application to write data beyond allocated memory boundaries. This memory corruption flaw enables local privilege escalation, potentially granting the attacker root/system-level privileges.

MitigationApply the available Apple security updates (iOS 14.7+, macOS Big Sur 11.5+, watchOS 7.6+, tvOS 14.7+, Security Update 2021-005/2021-004) to all affected devices. Restrict application installation to trusted sources and use endpoint detection to identify suspicious 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
Iphone OsOperating system
Affected:< 14.7
Mac Os XOperating system
Affected:>= 10.14, <= 10.14.5>= 10.15, <= 10.15.6= 10.14.6= 10.15.7
macOSOperating system
Affected:>= 11.0, < 11.5
TvosOperating system
Affected:< 14.7
WatchosOperating system
Affected:< 7.6

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
High
Availability
High

CVSS:3.1/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 checks

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

  1. Check iOS version on iPhone or iPad
    Go to Settings > General > About > Version, or run 'sw_vers' via Terminal on a Mac with Finder sync enabled for iOS devices
    Affected if Version is lower than 14.7 (for example, 14.6.x or earlier)
  2. Check macOS version
    Go to Apple menu > About This Mac > Version, or run 'sw_vers' in Terminal
    Affected if Version is 10.14.6, 10.14.5 or earlier, 10.15.7, 10.15.6 or earlier, or between 11.0 and 11.4.x (anything less than 11.5)
  3. Check tvOS version
    Go to Settings > General > About > Version on Apple TV, or check via Xcode device management
    Affected if Version is lower than 14.7
  4. Check watchOS version
    Open the Watch app on iPhone, go to General > About, or check via the Watch app settings
    Affected if Version is lower than 7.6

If any Apple device runs an OS version that falls within the affected ranges (iOS < 14.7, macOS 10.14.x through 10.15.7 or 11.0-11.4.x, tvOS < 14.7, watchOS < 7.6), the environment is potentially affected by this privilege escalation vulnerability.

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 7.6 / 11.5 / 14.7 or later
Fixed in 7.611.514.7
Interim mitigation

Apply the available Apple security updates (iOS 14.7+, macOS Big Sur 11.5+, watchOS 7.6+, tvOS 14.7+, Security Update 2021-005/2021-004) to all affected devices. Restrict application installation to trusted sources and use endpoint detection to identify suspicious applications.

Recommended fix High confidence

iOS 14.7+, macOS Big Sur 11.5+, watchOS 7.6+, tvOS 14.7+, Security Update 2021-004/2021-005 for older macOS

  1. Check current iOS version: Settings > General > About > Version
  2. Check current macOS version: Apple menu > About This Mac
  3. For iPhone/iPad: Go to Settings > General > Software Update and install iOS 14.7 or later
  4. For macOS Big Sur (11.x): Go to System Preferences > Software Update and install macOS 11.5 or later
  5. For macOS Catalina (10.15): Install Security Update 2021-004 Catalina via System Preferences > Software Update
  6. For macOS Mojave (10.14): Install Security Update 2021-005 Mojave via System Preferences > Software Update
  7. For Apple Watch: Go to Settings > General > Software Update and install watchOS 7.6 or later
  8. For Apple TV: Go to Settings > System > Software Updates and install tvOS 14.7 or later
Caveat Standard OS update considerations apply - backup data before updating, ensure compatibility with essential apps

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

Fix this in Iphone Os Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,380
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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-2021-30780 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