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Iphone OsOperating system · Apple

CVE-2021-30770

MEDIUM · 5.5 CVSS v3.1 Published 2021-09-08
Fix available
A fix is available. Upgrade to 7.6 / 14.7 or later.
See remediation →
57/100
Remediation priority · Elevated
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 validation. This issue is fixed in iOS 14.7, tvOS 14.7, watchOS 7.6. An attacker that has already achieved kernel code execution may be able to bypass kernel memory mitigations.

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

A logic issue in iOS 14.7, tvOS 14.7, and watchOS 7.6 allows an attacker who has already achieved kernel code execution to bypass kernel memory mitigations. This is a defense-in-depth bypass that weakens memory protection mechanisms once an attacker has already gained kernel-level access.

MitigationApply the vendor-supplied updates (iOS 14.7+, tvOS 14.7+, watchOS 7.6+) to affected devices. This vulnerability requires kernel code execution as a prerequisite, so prioritize patching to prevent escalation of existing compromises.

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
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
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS:3.1/AV:L/AC:L/PR:L/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 or iPad
    Open Settings > General > About and look at the 'Version' field. Compare the version number to 14.7 (any version below 14.7 is vulnerable).
    Affected if The displayed version is less than 14.7 (for example, 14.6.1, 14.6, 14.5, etc.)
  2. Check tvOS version on Apple TV
    Go to Settings > General > About > Version on the Apple TV device. Compare to 14.7.
    Affected if The tvOS version shown is less than 14.7.
  3. Check watchOS version on Apple Watch
    On the paired iPhone, open the Watch app, go to My Watch > General > About, and check the watchOS version. Alternatively, check directly on the watch via Settings > General > About. Compare to 7.6.
    Affected if The watchOS version is less than 7.6.
  4. Assess for prior kernel-level compromise
    This vulnerability is only exploitable after an attacker has already achieved kernel code execution. Look for indicators such as: unexplained kernel extensions, suspicious kernel debugging flags enabled (nvram boot-args), unknown processes with root privileges, or unexpected system modifications. This requires forensic investigation and is difficult to detect.
    Affected if Evidence exists that kernel code execution has occurred on the device (this is a prerequisite for exploiting this specific vulnerability).

A device is affected only if it is running a vulnerable OS version (iOS < 14.7, tvOS < 14.7, or watchOS < 7.6) AND an attacker has already achieved kernel code execution, as this flaw is a post-exploitation defense bypass.

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 / 14.7 or later
Fixed in 7.614.7
Interim mitigation

Apply the vendor-supplied updates (iOS 14.7+, tvOS 14.7+, watchOS 7.6+) to affected devices. This vulnerability requires kernel code execution as a prerequisite, so prioritize patching to prevent escalation of existing compromises.

Recommended fix High confidence

iOS 14.7, tvOS 14.7, watchOS 7.6

  1. Check the current iOS version on the iPhone or iPad device by going to Settings > General > About > Version
  2. Check the current tvOS version on the Apple TV device by going to Settings > System > About > Version
  3. Check the current watchOS version on the Apple Watch by opening the Watch app on iPhone, going to General > About > Version
  4. If the iOS version is below 14.7, upgrade to iOS 14.7 or later via Settings > General > Software Update
  5. If the tvOS version is below 14.7, upgrade to tvOS 14.7 or later via Settings > System > Software Update
  6. If the watchOS version is below 7.6, upgrade to watchOS 7.6 or later via the Watch app on iPhone > General > Software Update

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

Fix this in Iphone Os Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,040
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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-2021-30770 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