CVE-2025-43506
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 · uneditedA logic error was addressed with improved error handling. This issue is fixed in macOS Tahoe 26.1. iCloud Private Relay may not activate when more than one user is logged in at the same time.
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 confidenceA logic error in macOS causes iCloud Private Relay to fail activation when more than one user is logged in simultaneously. The bug stems from improper error handling that incorrectly processes the multi-user session state, preventing the privacy feature from initializing despite being available and enabled.
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< 26.1CVSS 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
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/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 checksWork through these to decide whether this CVE applies to you.
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Check installed macOS versionGo to Apple menu > About This Mac and note the macOS version number (e.g., 26.0, 25.4, etc.)Affected if Version is earlier than 26.1 (e.g., 26.0, 25.x, 24.x)
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Verify iCloud Private Relay is enabledOpen System Settings > Apple ID > iCloud > Private Relay and confirm the toggle is turned onAffected if Private Relay shows as enabled but fails to initialize or activate
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Check for multiple logged-in usersOpen System Settings > Users & Groups to see if more than one user account exists, or use the command 'who' in Terminal to list currently logged-in usersAffected if Multiple user sessions are active simultaneously on the system
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Confirm Private Relay activation failureObserve the Private Relay status in System Settings - it may show as unavailable, fail to load, or display an error despite being enabledAffected if Private Relay is enabled but shows as unavailable or fails to activate, especially in multi-user environments
You are affected if running macOS versions earlier than 26.1, have multiple users logged in simultaneously, and iCloud Private Relay fails to activate despite being enabled.
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 · scoped26.1
Update macOS to version Tahoe 26.1 or later, which contains the corrected error handling logic for iCloud Private Relay multi-user scenarios.
macOS Tahoe 26.1
- 1. Back up your Mac using Time Machine or another backup solution before upgrading.
- 2. Ensure your Mac is connected to power and has sufficient storage space.
- 3. Open System Settings (or System Preferences on older macOS).
- 4. Navigate to General > Software Update.
- 5. Check for updates - macOS Tahoe 26.1 should appear as available.
- 6. Click "Download and Install" to download and apply the macOS Tahoe 26.1 update.
- 7. Follow any on-screen prompts and restart when requested.
- 8. After updating, verify the version by going to System Settings > General > About and confirming the version shows 26.1 or later.
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation1.0 h
- Implementation1.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-43506 — 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-2025-43506 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
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