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MeetingsApplication · Zoom

CVE-2021-34409

HIGH · 7.8 CVSS v3.1 Published 2021-09-27
Fix available
A fix is available. Upgrade to 5.1.0 / 5.2.0 or later.
See remediation →
80/100
Remediation priority · High
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
It was discovered that the installation packages of the Zoom Client for Meetings for MacOS (Standard and for IT Admin) installation before version 5.2.0, Zoom Client Plugin for Sharing iPhone/iPad before version 5.2.0, and Zoom Rooms for Conference before version 5.1.0, copy pre- and post- installation shell scripts to a user-writable directory. In the affected products listed below, a malicious actor with local access to a user's machine could use this flaw to potentially run arbitrary system commands in a higher privileged context during the installation process.

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

The Zoom Client for Meetings, Plugin, and Zoom Rooms installation packages for MacOS write pre- and post-installation shell scripts to a user-writable directory. A locally authenticated attacker with access to the user's machine can modify these scripts before or during installation, causing them to execute with elevated privileges during the installation process, achieving local privilege escalation.

MitigationUpdate Zoom Client for Meetings and Plugin to version 5.2.0 or later, and Zoom Rooms for Conference to version 5.1.0 or later. These versions write scripts to non-user-writable locations.

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
MeetingsApplication
Affected:< 5.2.0
RoomsApplication
Affected:< 5.1.0
Screen SharingApplication
Affected:< 5.2.0

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
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/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 installed Zoom products
    On macOS, check /Applications for Zoom apps or run: ls /Applications | grep -i zoom
    Affected if Any Zoom Meetings, Zoom Rooms, or Zoom Screen Sharing is installed
  2. Check Zoom Meetings version
    Open Zoom app, click Zoom icon top-right, select 'About Zoom' or run: defaults read /Applications/Zoom.us.app/Contents/Info CFBundleVersion 2>/dev/null
    Affected if Version is less than 5.2.0 (e.g., 5.1.x or earlier)
  3. Check Zoom Rooms version
    Open Zoom Rooms app, go to Account Settings > About, or check app bundle version as above
    Affected if Version is less than 5.1.0 (e.g., 5.0.x or earlier)
  4. Check Zoom Screen Sharing version
    Check the app version in /Applications/ZoomStandardMacShare.app or similar Screen Sharing app bundle
    Affected if Version is less than 5.2.0

A user is affected if any Zoom Meetings, Zoom Rooms, or Zoom Screen Sharing product is installed with a version lower than 5.2.0 for Meetings/Screen Sharing or lower than 5.1.0 for Zoom Rooms.

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 5.1.0 / 5.2.0 or later
Fixed in 5.1.05.2.0
Interim mitigation

Update Zoom Client for Meetings and Plugin to version 5.2.0 or later, and Zoom Rooms for Conference to version 5.1.0 or later. These versions write scripts to non-user-writable locations.

Recommended fix High confidence

Meetings: 5.2.0+ | Rooms: 5.1.0+ | Screen Sharing Plugin: 5.2.0+

  1. 1. Close all running Zoom applications (Meetings, Rooms, or any Zoom plugins)
  2. 2. Navigate to the official Zoom download page at explore.zoom.us
  3. 3. Download the appropriate installer for your product: Zoom Client for Meetings version 5.2.0 or later, Zoom Rooms version 5.1.0 or later, or Zoom Client Plugin for Sharing iPhone/iPad version 5.2.0 or later
  4. 4. Run the installer and follow the on-screen prompts to complete the installation
  5. 5. Verify the installed version by opening Zoom and checking About > Version to confirm you have a fixed release

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

Fix this in Meetings Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing2.0 h
  • Review / QA2.0 h
16.0 hours of engineering $2,900
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,640.

Scan for this in your stack

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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-2021-34409 in production — separate from our analysis above.

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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