CVE-2021-34423

What it is

A buffer overflow vulnerability was discovered in Zoom Client for Meetings (for Android, iOS, Linux, macOS, and Windows) before version 5.8.4, Zoom Client for Meetings for Blackberry (for Android and iOS) before version 5.8.1, Zoom Client for Meetings for intune (for Android and iOS) before version 5.8.4, Zoom Client for Meetings for Chrome OS before version 5.0.1, Zoom Rooms for Conference Room (for Android, AndroidBali, macOS, and Windows) before version 5.8.3, Controllers for Zoom Rooms (for Android, iOS, and Windows) before version 5.8.3, Zoom VDI Windows Meeting Client before version 5.8.4, Zoom VDI Azure Virtual Desktop Plugins (for Windows x86 or x64, IGEL x64, Ubuntu x64, HP ThinPro OS x64) before version 5.8.4.21112, Zoom VDI Citrix Plugins (for Windows x86 or x64, Mac Universal Installer & Uninstaller, IGEL x64, eLux RP6 x64, HP ThinPro OS x64, Ubuntu x64, CentOS x 64, Dell ThinOS) before version 5.8.4.21112, Zoom VDI VMware Plugins (for Windows x86 or x64, Mac Universal Installer & Uninstaller, IGEL x64, eLux RP6 x64, HP ThinPro OS x64, Ubuntu x64, CentOS x 64, Dell ThinOS) before version 5.8.4.21112, Zoom Meeting SDK for Android before version 5.7.6.1922, Zoom Meeting SDK for iOS before version 5.7.6.1082, Zoom Meeting SDK for macOS before version 5.7.6.1340, Zoom Meeting SDK for Windows before version 5.7.6.1081, Zoom Video SDK (for Android, iOS, macOS, and Windows) before version 1.1.2, Zoom On-Premise Meeting Connector Controller before version 4.8.12.20211115, Zoom On-Premise Meeting Connector MMR before version 4.8.12.20211115, Zoom On-Premise Recording Connector before version 5.1.0.65.20211116, Zoom On-Premise Virtual Room Connector before version 4.4.7266.20211117, Zoom On-Premise Virtual Room Connector Load Balancer before version 2.5.5692.20211117, Zoom Hybrid Zproxy before version 1.0.1058.20211116, and Zoom Hybrid MMR before version 4.6.20211116.131_x86-64. This can potentially allow a malicious actor to crash the service or application, or leverage this vulnerability to execute arbitrary code.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of data exposure, data tampering, service disruption.

Exploit odds

3.3% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2021-11-24 17:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 03:55 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 3.3% in the next 30 days (EPSS).
• Severity: 9.8 CRITICAL (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2021-11-24 17:15 UTC

Last modified

2026-06-17 03:55 UTC

Exploit probability

3.3% · EPSS, next 30 days

Weakness

CWE-120 · Classic buffer overflow

Record status

Modified

Affected

• Zoom Meetings < 5.8.3
• Zoom Meetings < 5.8.4
• Zoom Meetings For Blackberry < 5.8.1
• Zoom Meetings For Intune < 5.8.4
• Zoom Meetings For Chrome Os < 5.0.1
• Zoom Rooms For Conference Rooms < 5.8.3
• Zoom Controllers For Zoom Rooms < 5.8.3
• Zoom Virtual Desktop Infrastructure < 5.8.4

Attack profile CVSS 3.1 · 9.8

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2021-34423.md and follow it. Check whether this project is affected by CVE-2021-34423. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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