CVE-2023-42940
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 session rendering issue was addressed with improved session tracking. This issue is fixed in macOS Sonoma 14.2.1. A user who shares their screen may unintentionally share the incorrect content.
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 session rendering vulnerability in macOS Sonoma 14.2.1 screen sharing allows users to inadvertently share incorrect content due to improper session tracking. The flaw causes content confusion where the displayed window or desktop view may not match what the user intends to share.
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>= 14.0, < 14.2.1CVSS 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
- Low
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/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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Verify the installed macOS versionOpen System Settings > General > About, or run 'sw_vers' in Terminal, and note the version number (e.g., 14.0, 14.1, 14.2)Affected if The version is 14.0, 14.1, or 14.2 (any build before 14.2.1)
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Confirm the specific macOS buildRun 'sw_vers -buildVersion' in Terminal to get the exact build number (e.g., 23A344, 23B505, 23C71)Affected if The build is earlier than the build shipped with 14.2.1 (the specific build number for 14.2.1 varies by Mac model)
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Check if Screen Sharing is enabledGo to System Settings > General > Sharing > Screen Sharing, or run 'system_profiler SPSharingDataType' in TerminalAffected if Screen Sharing is turned ON and the macOS version falls in the affected range
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Identify active screen sharing sessionsRun 'screen_sharing_ports' or check for active connections on port 5900 (the VNC screen sharing port) using 'lsof -i :5900'Affected if An active screen sharing session exists while running an affected macOS version
You are affected if your macOS version is 14.0, 14.1, or 14.2 (any build before 14.2.1) AND you have Screen Sharing enabled or actively use screen sharing functionality.
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 · scoped14.2.1
Update to macOS Sonoma 14.2.1 or later. Avoid screen sharing functionality until the patch is applied, as unintended content exposure could leak sensitive information to meeting participants.
macOS Sonoma 14.2.1 or later
- Check the current macOS version by going to System Settings > General > About
- Back up important data using Time Machine or another backup solution before proceeding with the update
- Open System Settings > General > Software Update
- If macOS Sonoma 14.2.1 or later is available, click Update Now to download and install the update
- Alternatively, download macOS Sonoma 14.2.1 from the Apple Support downloads page and install manually
- After installation, verify the update by checking System Settings > General > About to confirm version 14.2.1 or later is installed
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation1.0 h
- Testing4.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-42940 — 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-2023-42940 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