CVE-2021-34415Network attack vector

Unauthenticated crash via unchecked PDU allocation count

Published Sep 27, 2021 · Updated Aug 4, 2024

Resource exhaustion in Zoom Meeting Connector before 4.6.358.20210205 allows remote attackers to crash the controller via network packets. The Zone Controller trusts the cnt field in an incoming protocol data unit and performs the requested allocations without validating or limiting that count. No authentication or user interaction is required; a crafted packet can exhaust controller resources and terminate on-premises meeting service.

CVSS severity7.5
High
EPSS probability0.98%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in Zoom Meeting Connector before 4.6.358.20210205 allows remote attackers to crash the controller via network packets. The Zone Controller trusts the cnt field in an incoming protocol data unit and performs the requested allocations without validating or limiting that count. No authentication or user interaction is required; a crafted packet can exhaust controller resources and terminate on-premises meeting service.

The record

CVE
CVE-2021-34415
Published
Sep 27, 2021
Updated
Aug 4, 2024
Vendor
Zoom Video Communications, Inc.
Product
Zoom Meeting Connector
Classifications
CWE-770, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 27, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=The Zoom On-Premise Meeting Connector Controller before version 4.6.358.20210205

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Zoom Video Communications, Inc. · Zoom Meeting Connectorversion=The Zoom On-Premise Meeting Connector Controller before version 4.6.358.20210205

Published CVSS scores

7.8NIST National Vulnerability DatabaseAV:N/AC:L/Au:N/C:N/I:N/A:C
7.5NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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