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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 17 Nov 2021.
IpadosOperating system · Apple

CVE-2021-30665

HIGH · 8.8 CVSS v3.1 Published 2021-09-08
Fix available
A fix is available. Upgrade to 7.4.1 / 11.3.1 or later.
See remediation →
100/100
Remediation priority · Urgent
In the wild Remotely reachable 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
A memory corruption issue was addressed with improved state management. This issue is fixed in watchOS 7.4.1, iOS 14.5.1 and iPadOS 14.5.1, tvOS 14.6, iOS 12.5.3, macOS Big Sur 11.3.1. Processing maliciously crafted web content may lead to arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited..

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

This is a WebKit memory corruption vulnerability in multiple Apple operating systems (iOS, iPadOS, watchOS, tvOS, macOS) that allows arbitrary code execution when processing maliciously crafted web content. The issue was addressed with improved state management and was actively exploited as a zero-day.

MitigationApply the available security updates (iOS 14.5.1/iPadOS 14.5.1, watchOS 7.4.1, tvOS 14.6, iOS 12.5.3, macOS Big Sur 11.3.1) to all affected devices. This is a critical zero-day requiring immediate patching.

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:< 14.5.1
Iphone OsOperating system
Affected:< 12.5.3>= 13.0, < 14.5.1
macOSOperating system
Affected:< 11.3.1
TvosOperating system
Affected:< 14.6
WatchosOperating system
Affected:< 7.4.1

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
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/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. Identify your Apple device and operating system
    Determine whether the device runs iOS, iPadOS, macOS, tvOS, or watchOS. On iOS/iPadOS, go to Settings > General > About. On macOS, click Apple menu > About This Mac. On tvOS/watchOS, go to Settings > General > About.
    Affected if The device runs any of the listed Apple operating systems.
  2. Check the installed iOS or iPadOS version
    On iOS or iPadOS, view the version number in Settings > General > About. Compare it to the affected ranges: < 12.5.3, >= 13.0 and < 14.5.1, or < 14.5.1 for iPadOS.
    Affected if The version is 12.5.3 or lower, or between 13.0 and 14.5.1.
  3. Check the installed macOS version
    On macOS, view the version in Apple menu > About This Mac. Compare it to the affected range: < 11.3.1.
    Affected if The macOS version is 11.3.1 or lower (including all versions of macOS Big Sur prior to 11.3.1).
  4. Check the installed tvOS or watchOS version
    On tvOS, go to Settings > General > About > Version. On watchOS, go to Settings > General > About > Watch Version. Compare to affected ranges: tvOS < 14.6, watchOS < 7.4.1.
    Affected if The tvOS version is below 14.6 or the watchOS version is below 7.4.1.
  5. Confirm WebKit is in use
    Recognize that WebKit is the browser engine used by Safari and embedded web views in apps on all affected Apple platforms. Any use of Safari or apps with web content triggers the vulnerable code path.
    Affected if Safari or any app displaying web content is used on an affected OS version.

You are affected if your Apple device runs any iOS, iPadOS, macOS, tvOS, or watchOS version below the patched releases (iOS 14.5.1/iPadOS 14.5.1, macOS 11.3.1, watchOS 7.4.1, tvOS 14.6, or iOS 12.5.3 for older devices) and you use Safari or apps with web content.

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 7.4.1 / 11.3.1 / 12.5.3 or later
Fixed in 7.4.111.3.112.5.3
Interim mitigation

Apply the available security updates (iOS 14.5.1/iPadOS 14.5.1, watchOS 7.4.1, tvOS 14.6, iOS 12.5.3, macOS Big Sur 11.3.1) to all affected devices. This is a critical zero-day requiring immediate patching.

Recommended fix High confidence

iOS 14.5.1 (or iOS 12.5.3 for older devices), iPadOS 14.5.1, macOS Big Sur 11.3.1, watchOS 7.4.1, tvOS 14.6

  1. Identify the Apple device (iPhone, iPad, Mac, Apple Watch, or Apple TV) that needs to be updated
  2. Check the current OS version on the device in Settings > General > About (iOS/iPadOS/watchOS/tvOS) or System Preferences > About (macOS)
  3. For iPhone/iPad: If running iOS/iPadOS 13.x or 14.x, upgrade to version 14.5.1; if running iOS 12.x and cannot upgrade to 14.x, upgrade to iOS 12.5.3
  4. For Mac: Upgrade to macOS Big Sur 11.3.1 via System Preferences > Software Update
  5. For Apple Watch: Upgrade to watchOS 7.4.1 via the Watch app on iPhone
  6. For Apple TV: Upgrade to tvOS 14.6 via Settings > System > Software Updates
  7. Ensure the device is connected to Wi-Fi and power during the update process
Caveat Standard OS upgrade risks apply (app compatibility, data migration issues); iOS 12.5.3 is the final update for iPhone 5s and iPhone 6 devices

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

Fix this in Ipados Exploited in the wild — priority engagement
  • 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

Check whether your project pulls in CVE-2021-30665 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

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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-2021-30665 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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