CVE-2026-43666
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 · uneditedAn out-of-bounds write issue was addressed with improved bounds checking. This issue is fixed in iOS 18.7.9 and iPadOS 18.7.9, iOS 26.5 and iPadOS 26.5, macOS Sequoia 15.7.7, macOS Sonoma 14.8.7, macOS Tahoe 26.5, tvOS 26.5, visionOS 26.5, watchOS 26.5. An attacker on the local network may be able to cause a denial-of-service.
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 confidenceAn out-of-bounds write vulnerability in Apple operating systems that could allow a remote attacker on the local network to cause denial-of-service. The issue stems from insufficient bounds checking in memory operations, which could lead to writing beyond allocated buffer boundaries.
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< 18.7.9>= 26.0, < 26.5< 18.7.9>= 26.0, < 26.5>= 14.0, < 14.8.7>= 15.0, < 15.7.7>= 26.0, < 26.5< 26.5< 26.5< 26.5CVSS 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
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 checksWork through these to decide whether this CVE applies to you.
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Identify your Apple device typeDetermine whether the device is an iPhone, iPad, Mac, Apple TV, Apple Watch, or Apple Vision. This can be done via System Settings > About or System Information on Mac.Affected if The device is any of these Apple products and the OS version falls within affected ranges
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Check iOS version on iPhoneGo to Settings > General > About and note the iOS version number shown next to 'Software Version'.Affected if iOS version is less than 18.7.9 OR is 26.0 or higher but less than 26.5
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Check iPadOS version on iPadGo to Settings > General > About and note the iPadOS version number shown next to 'Software Version'.Affected if iPadOS version is less than 18.7.9 OR is 26.0 or higher but less than 26.5
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Check macOS version on MacClick Apple menu > About This Mac. The version number appears below the macOS name (e.g., Sonoma 15.7, Sequoia 26.0).Affected if macOS version is 14.0 or higher but less than 14.8.7, OR 15.0 or higher but less than 15.7.7, OR 26.0 or higher but less than 26.5
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Check tvOS, watchOS, or visionOS versionOn Apple TV: go to Settings > General > About > Version. On Apple Watch: open the Watch app on iPhone > General > About. On Apple Vision: go to Settings > General > About.Affected if tvOS, watchOS, or visionOS version is less than 26.5
The device is affected if its installed OS version falls within any of the vulnerable version ranges listed for its product category.
Generated from the published advisory. Verify against your own configuration.
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 · scoped14.8.715.7.718.7.9
Apply the vendor-supplied patches by updating affected devices to iOS 18.7.9/iPadOS 18.7.9, iOS 26.5/iPadOS 26.5, macOS Sequoia 15.7.7, macOS Sonoma 14.8.7, macOS Tahoe 26.5, tvOS 26.5, visionOS 26.5, or watchOS 26.5 as appropriate.
Upgrade to iOS 18.7.9/iPadOS 18.7.9, iOS 26.5/iPadOS 26.5, macOS Sonoma 14.8.7, macOS Sequoia 15.7.7, macOS Tahoe 26.5, tvOS 26.5, visionOS 26.5, or watchOS 26.5 as appropriate for the device type
- Identify the Apple device type (iPhone, iPad, Mac, Apple TV, Apple Vision Pro, or Apple Watch) that needs remediation
- Check the current installed software version in Settings > General > About (iOS/iPadOS/watchOS/visionOS) or System Settings/About (macOS/tvOS)
- For iPhone or iPad: Upgrade to iOS 18.7.9/iPadOS 18.7.9 or iOS 26.5/iPadOS 26.5 depending on which major version line the device is on
- For Mac: Upgrade to macOS Sonoma 14.8.7, macOS Sequoia 15.7.7, or macOS Tahoe 26.5 depending on which major version line the Mac is running
- For Apple TV: Upgrade to tvOS 26.5
- For Apple Vision Pro: Upgrade to visionOS 26.5
- For Apple Watch: Upgrade to watchOS 26.5
- After upgrade, verify the new version is installed and the vulnerability is patched
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-43666 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-43666 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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