CVE-2021-1524Network attack vector

Call disconnection via unvalidated API request

Published Jun 16, 2021 · Updated Nov 7, 2024

Improper input validation in Cisco Meeting Server 3.1 and 3.1.1 allows remote authenticated users to disconnect all call participants. The API accepts a malicious request without proper validation, but Cisco has not disclosed the affected endpoint or the request fields that trigger the failure. API credentials and network access to the HTTPS Web Admin interface are required, and successful exploitation interrupts active calls without reported confidentiality or integrity impact.

CVSS severity4.3
Medium
EPSS probability1.10%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Cisco Meeting Server 3.1 and 3.1.1 allows remote authenticated users to disconnect all call participants. The API accepts a malicious request without proper validation, but Cisco has not disclosed the affected endpoint or the request fields that trigger the failure. API credentials and network access to the HTTPS Web Admin interface are required, and successful exploitation interrupts active calls without reported confidentiality or integrity impact.

The record

CVE
CVE-2021-1524
Published
Jun 16, 2021
Updated
Nov 7, 2024
Vendor
ClamAV
Product
Cisco Meeting Server
Classifications
CWE-20, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 16, 2021CVE publishedPublication date reported by the CVE source.
  2. Nov 7, 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=n/a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

ClamAV · Cisco Meeting Serverversion=n/a

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
4.0NIST NVDAV:N/AC:L/Au:S/C:N/I:N/A:P
4.3Cisco Systems, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:X/RL:X/RC:X

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
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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