NVD / CVE Program· CNA Zoom

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

Noroxi assessment

Priority: Monitor (action score 31/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.19% (FIRST EPSS).
Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
According to the record, no fixed version is available yet.

Low priority for now. Update when a fix is released; follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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 7.8 · v3.1—No exploit No fix recorded

Local privilege escalation

Published: Sep 27, 2021
Updated: Jun 16, 2026
EPSS: 0.1% · 9th percentile
CWE: CWE-732

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 31 / 40 · 7.8 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.1%

CNA vs NVD score

NVD: 7.8
CNA · Zoom: 7.8; agree

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
No fixed version yet

If any of these changes, we'll tell you in the daily email digest.

Running WordPress? Scan your site free with WP Lens

Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

We use this product, ask for help

Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
zoom	meetings	cpe:2.3:a:zoom:meetings
zoom	rooms	cpe:2.3:a:zoom:rooms
zoom	screen sharing	cpe:2.3:a:zoom:screen_sharing

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

zoom meetingsbefore 5.2.0
zoom roomsbefore 5.1.0
zoom screen sharingbefore 5.2.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Zoom). Independent of NVD's CPE analysis and usually ahead of it.

Zoom Video Communications Inc Zoom Client for Meetings for MacOS (Standard and for IT Admin)
- unspecified and later · before 5.2.0affected
Zoom Video Communications Inc Zoom Client Plugin for Sharing iPhone/iPad
- unspecified and later · before 5.2.0affected
Zoom Video Communications Inc Zoom Rooms for Conference
- unspecified and later · before 5.1.0affected

Same product

zoom: all records

Other highest-scoring records for the same primary product.

CVE-2021-34423Buffer overflow in Zoom client and other products
40Plan
CVE-2021-33907The Zoom Client for Meetings for Windows in all versions before 5.3.0 fails to properly validate the certificate information used to sign .m
40Plan
CVE-2022-28763Improper URL parsing in Zoom Clients
38Monitor

Published before and after this one in the same product

← EarlierCVE-2020-11877Apr 17, 2020 · airhost.exe in Zoom Client for Meetings 4.6.11 uses 3423423432325249 as the Initialization Vector (IV) for AES-256 CBC encryption.
30Monitor
← EarlierCVE-2021-34408Sep 27, 2021 · The Zoom Client for Meetings for Windows in all versions before version 5.3.2 writes log files to a user writable directory as a privileged
31Monitor
Later →CVE-2021-34412Sep 27, 2021 · During the installation process for all versions of the Zoom Client for Meetings for Windows before 5.4.0, it is possible to launch Internet
31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Lockheed Martin Red Team

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

Someone with local access to the system can trigger it.
A low-privileged account is enough.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: high · data can be read
Integrity: high · data or configuration can be modified
Availability: high · the service can be disrupted

Attack vector: Local
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
Availability impact: High

Weakness class (CWE)

CWE-732 · Incorrect Permission Assignment for Critical Resource

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

explore.zoom.us/en/trust/security/security-bulletin

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records