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CVE Record

CVE-2021-34409: Zoom Client Installer Local Privilege Escalation

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.

HighCVSS 7.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

This is a macOS local privilege escalation in older Zoom installers. If a local attacker already has access to a user’s machine, they may be able to abuse the affected installation process to run system commands with higher privileges. The business risk is mainly compromised endpoints where outdated Zoom installers or deployment packages remain in use.

Executive priority

Treat as a priority endpoint hygiene issue, especially in managed macOS fleets. It is not described as remotely exploitable, but outdated installers can turn local footholds into higher-privilege compromise. Remove vulnerable packages and verify fixed versions across deployment channels.

Technical view

Affected Zoom macOS installers copied pre- and post-install shell scripts into a user-writable directory. A low-privileged local actor could potentially influence that installation workflow and execute arbitrary commands in a higher-privileged context. Affected products are Zoom Client for Meetings for macOS before 5.2.0, the iPhone/iPad sharing plugin before 5.2.0, and Zoom Rooms for Conference before 5.1.0.

Likely exposure

Exposure is limited to macOS systems using the affected Zoom installers or holding outdated deployment packages. Organizations with managed software distribution, shared installer repositories, or delayed Zoom updates should verify both installed versions and retained installer artifacts.

Exploitation context

The CVE requires local access and is rated high with CVSS 7.8. The source bundle does not show CISA KEV listing or any cited evidence of active exploitation. Attack impact could be serious after initial local access because execution may occur in a higher-privileged context.

Researcher notes

The provided evidence identifies the installer behavior and fixed version thresholds but does not include proof-of-concept details, exploitation telemetry, or deeper root-cause analysis. Focus validation on package provenance, installer retention, and macOS deployment workflows rather than only currently running applications.

Mitigation direction

  • Update Zoom Client for Meetings for macOS to version 5.2.0 or later.
  • Update Zoom Client Plugin for Sharing iPhone/iPad to version 5.2.0 or later.
  • Update Zoom Rooms for Conference to version 5.1.0 or later.
  • Remove outdated Zoom installer packages from MDM, software portals, and shared repositories.
  • Check Zoom’s security bulletin for current vendor guidance.

Validation and detection

  • Inventory macOS endpoints for the affected Zoom products and versions.
  • Review MDM and software distribution repositories for old Zoom installer packages.
  • Confirm deployment baselines require the fixed Zoom versions or later.
  • Check endpoint management logs for recent installs using affected packages.
  • Document exceptions where legacy Zoom components remain installed.
Prepared
Confidence
medium
Sources
3

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

description · low confidence lookup

Privilege behavior lookup

The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2021-34409 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.8 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
2Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.8CVSS 3.1HighCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H1.16Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

7.8High
CVSS 3.1 vector shape for CVE-2021-34409Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
Zoom Video Communications IncZoom Client for Meetings for MacOS (Standard and for IT Admin)unspecifiedListed
Zoom Video Communications IncZoom Client Plugin for Sharing iPhone/iPadunspecifiedListed
Zoom Video Communications IncZoom Rooms for ConferenceunspecifiedListed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.